I recently salvaged a mercury vapor security light from a demolition site that I plan to hold on to. I would post photos, but it's saying my files are too large. This is one of those typical outdoor home fixtures that was made for decades. I'm guessing it was made in the 1960s or 70s, but it could be newer. There's no wiring diagram or any paper label that has anything that looks like a date; however, there is what looks like a serial number on a piece of plastic housing between the ballast and the socket. The number is 058-85-40066, with the number "4" printed below. I've heard you can sometimes identify the manufacture date from this. I'm also guessing the "93 T3" elsewhere on the ballast means it's a T3 ballast. The writing on the bulb is blurry, but I was able to make out that it is a Philips 175W H35KC /dx bulb. Is there a way to ID the manufacture date of the bulb from any of this?