Welcome back Halfa. I wouldn't worry too much about the separation issue, it was pretty rare. I have a pair of P38s that were built in 2009, been used a lot, and no problems at all. They were a prototype built in Indy, no serial numbers. I did get the center, P312 sub, and a pair of P17b for surrounds a few years later.
7K for a pair of P39s is a good buy. I would move quickly or they might disappear. What color are they, they are all beautiful, I'm partial to merlot.
There's a very interesting photo of all 3 towers together, the 39s are massive. My friend is the lead acoustical engineer in Indy, he made the comment once that if the P39 had a larger cabinet, they could really sound good.