It just so happened I found a used copy of the Rhinoceros Sutra from Gāndhāra and in that I was already reading about the Pratimokṣa of the Mahāsāṃghikas I saw the texts were linked to the Pratyekabuddhas and previous buddhas respectively. I noted both were identified as early Buddhist Texts.
Were they in any way contemporary or harmonious in perspective?
And to be clear, it was the last 8 verses of the Pratimokṣa which each was spoken by one of the last 7 Buddhas that was alleged to be an original form of Pratimokṣa and old.
LR
[Gāndhārī: Khargaviṣaṇa-sutra: A Gandhari Version of the Rhinoceros Sutra: British Library]
[Pribish, Charles S., Buddhist Monastic Discipline, 1996, Motilal Banarsidass, India.]