They may not be ProV's. Usually you get test balls, but they do not tell you what they are (ProV, ProV1x, AVX, etc), so you don't slant your review.

Does your mailman play golf??? I would think you would be referring to testing that took place last fall. If you got something recently it would be a scam. Last fall a small population was notified that they might be receiving some test balls and if they did, to post results on this site. They could possibly do something similar later in the year for something from the non-ProV1 line of balls although they do not normally perform extensive testing and research from as many people on those models.

I've been lucky enough to be selected for prototype testing twice. Each time it was for a new Pro v1/V1x model. I was sent the balls a few months before they actually hit the shelves. Titleist's pattern has been to update the Pro V1 line every two years, making them due in 2021, usually early in the year. I would expect prototype testers would be notified around this time next year.