Those look like they could be night sights on the OP's gun to me. Clean off the rears with a q-tip and acetone and look for little glass (sapphire) disks where the dots are. If so call Trijicon and have them relamped for $57.
Hey, sorry for the late reply.
Thank you but I looked, I don't see any lamps in there and while I DO wear glasses, I'm not THAT blind. I'm going to get the SA-01 sights but I'm going to keep all the old stuff because I hate to throw something that old away. One of these years the 5900 series will be legit antiques and historical objects so it makes sense to me to keep all the original parts.