Yeah, I have found a few PM's who were "used to be technical". To be honest I found it a bit frustrating at times as they would think they knew enough to make (some of the) technical decisions, when I felt that I should actually be making those decisions as was the one actually getting my hands dirty with the code. Plus I had more experience as a developer than them, as they had transitioned to PM and hadn't actually been building stuff for a while.