NOT TRUE!

NOTHING is "on PRIA" except FAA records. Everything else requires that a form be sent to previous employers, and said employers must reply with the legally required info.

You are REQUIRED by LAW to do PRIA forms for previous aviation employers of any sort, including part 91. It would probably be a violation of federal law (specifically the Pilot Records Improvement Act) to fail to report a previous aviation employer when applying to a part 121 carrier. Unless there is a look-back window which has expired, you'd better talk to a lawyer before you play games with the feds. Since you got paid, I suspect that counts as employment.