I have collected what references I could find to Revati in the Vedas and Mahabharata.
1) from: Rig Veda Book 5 Hymn 51
सवस्ति मित्रावरुणा सवस्ति पथ्ये रेवति | let Revati be safe in her path.
सवस्ति न इन्द्रश चाग्निश च सवस्ति नो अदिते कर्धि ||
सवस्ति पन्थाम अनु चरेम सूर्याचन्द्रमसाव इव |
पुनर ददताघ्नता जानता सं गमेमहि ||
This verse refers to the path of Revathi. That could be the east to west path, observable daily, and the interest in Revathi could be that she was the ‘first’ or ‘spring’ star.
Or it could be that the path refers to the precession of equinoxes – as is indicated by the Mahabharata story. To me this would mean, that the path of Revati was observed by the time this hymn was written. To observe a precession of 1 degree, it would take a 60 year cycle. (Indian year names cycle after 60).
Between Hipparchus and his student Ptolemy, the greeks figured out the precession of equinoxes from 150 BC to 150 AD, over a period of 300 years, by observing Spica (Chitra). It is reasonable to think that a family of rishis, would not need more than that period of time to observe the same thing – the difference being that they observed the Revathi Nakshatram. If they had better observatories and better maths, they could have done it in a shorter period of time. I am sure that at least these rishis knew about it: Mrkandu, and his son Markandeya, Vasishtha, his son Shakthi, his grandson Parasara and great grandson Vyasa, Bhishma and Krishna.
2) Rig Veda Book 10 Hymn 86
नह्यस्यापरं चन जरसा मरते पतिर्विश्वस्मादिन्द्र उत्तरः ||
नाहमिन्द्राणि रारण सख्युर्व्र्षाकपेरते |
यस्येदमप्यं हविः परियं देवेषु गछति विश्वस्मादिन्द्रौत्तरः ||
वर्षाकपायि रेवति सूपुत्र आदु सुस्नुषे |
घसत त इन्द्रौक्षणः परियं काचित्करं हविर्विश्वस्मादिन्द्रौत्तरः ||
उक्ष्णो हि मे पञ्चदश साकं पचन्ति विंशतिम |
(I am yet to translate this mantram.)
3) yajur Veda kanda 4 iv. 4. 10. This mantram, of the Yajur Veda, starts with Krttika as the first nakshatram and states that Pusan is the deity of Revati.
(Thou art) Krttikas, the Naksatra, Agni, the deity; ye are the radiances of Agni, of Prajapati, of the creator, of Soma; to the Re thee, to radiance thee, to the shining thee, to the blaze thee, to the light thee
b (Thou art) Rohini the Naksatra, Prajapati the deity; Mrgaçirsa the Naksatra, Soma the deity; Ardra the Naksatra, Rudra the deity; the two Punarvasus the Naksatra, Aditi the deity; Tisya the Naksatra, Brhaspati the deity; the Açresas the Naksatra, the serpents the deity; the Maghas the Naksatra, the fathers the deity; the two Phalgunis the Naksatra , Aryaman the deity; the two Phalgunis the Naksatra, Bhaga the deity; Hasta the Naksatra, Savitr the deity; Citra the Naksatra, Indra the deity; Svati the Naksatra, Vayu the deity; the two Viçakhas the Naksatra, Indra and Agni the deity; Anruradha the Naksatra, Mitra the deity; Rohini the Naksatra, Indra the deity; the two Viçrts the Naksatra; the fathers the deity; the Asadhas the Naksatra, the waters the deity; the Asadhas the Naksatra, the All-gods the deity; Çrona the Naksatra, Visnu the deity; Çravistha the Naksatra, the Vasus  the, deity; Çatabhisaj the Naksatra, Indra the deity; Prosthapadas the Naksatra, the goat of one foot the deity; the Prosthapadas the Naksatra, the serpent of the deep the deity; Revati the Naksatra, Pusan the deity; the two Açvayujs the Naksatra, the Açvins the deity; the Apabharanis the Naksatra, Yama the deity.
4) SECTION LXXXIII udyoga parva (Mahabharata): Krishna gets ready to go to hastinapura with the message of peace, under the Revati Nakshatra
….The night having passed away, a bright sun arose in the east. The hour called Maitra set in, and the rays of the sun were still mild. The month was (Kaumuda Kartika) under the constellation Revati. It was the season of dew, Autumn having departed. The earth was covered with abundant crops all around. It was at such a time that Janardana…….
“Bhishma said, ‘In the month of Margasirsha, when the moon comes in conjunction with the asterism called Mula, when his two feet are united with that very asterism, O king, when Rohini is in his calf, when his knee-joints are in Aswini, and his shins are in the two Ashadhas, when Phalguni makes his anus, and Krittika his waist, when his navel is in Bhadrapada, his ocular region in. Revati, and his back on the Dhanishthas, when Anuradha makes his belly, when with his two arms he reaches the Visakhas, when his two hands are indicated by Hasta, when Punarvasu, O king, makes his fingers, Aslesha his nails, when Jyeshtha is known for his neck, when by Sravana is pointed out his ears, and his mouth by Pushya, when Swati is said to constitute his teeth and lips, when Satabhisha is his smile and Magha his nose, when Mrigasiras is known to be in his eye, and Chitra in his forehead, when his head is in Bharani, when Ardra constitutes his hair, O king, the vow called Chandravrata should be commenced. Upon the completion of that vow, gift of ghee should be made unto Brahmanas conversant with the Vedas. As the fruit of that vow, one becomes possessed about knowledge. Indeed, one becomes, in consequence of such a vow, as full (of every blessed attribute) as the moon himself when he is at full.’”