With risk of sounding terse, we have no idea without a schematic and/or pictures. Do you have a schematic you can upload? If the amp has been fiddled with in the past, sure, it's possible somebody removed parts and didn't put them back in. It's more likely those parts aren't used in this model and you don't need to put them in. A schematic would tell you that. Look at the solder side. Does it look like something was soldered there at one time?
By the way, that was quite the nest!
Edit: Did you play through the amp on the LBL? The limiter is just to test initial function and for problems. When the amp is proved working correctly, you should remove the limiter before actually using the amp. Also, if there wasn't any hum and the amp is functioning normally, I don't see any reason to wholesale replace caps.