Speaking of Silverliners and Form 400s, both are still in service in my area (only two of the latter). I just need to figure out how to get them! I've already sent the outdoor lighting department at the POCO an email and they said they can't give away old streetlights. No reason given. Might have to try the local office.
I've had similar responses lately. As for the ITT Mercs, I know there are still some in my old neighborhood in the town I grew up in. All I gotta do is go down to Mississippi, and I bet I could load up with a few. There are also some old 1960s old GE Post Top lights (GE's 1960s version of the P17M) I used to have one, but it was an HPS and it was from the 1970s. Probably an original HPS Luminaire. I don't have a lot of my vintage lights anymore. I made the mistake of leaving them behind when I moved to Wisconsin, and when my parents sold their house, they threw my old lights out as junk. I still have some various parts though.