Bogen CHB-50 Rebuild

[physics]

Hi all!

As mentioned in the CHB-20 rebuild thread, my friend decided that 50W was a better fit for his needs so I am working on making a Bogen CHB-50 usable as a clean pedal platform. Schematic for the curious:
   

My primary mission right now is rebuilding the power supply with some new electrolytics and also a film cap to replace the paper-in-oil one from the bias supply. However, there are a few other caps (coupling caps) which I'm unsure on whether to replace or not. I think they are film types since they don't look like paper-in-oil caps that I have seen before, but I was hoping some of you would recognize them. I've heard chatter on other forums that old coupling caps between stages should be replaced too even if film types, but given the same forums also worship at the altar of all sorts of audiophoolery that doesn't seem like a reliable source of advice. Are there any guidelines for determining whether coupling caps are bad, assuming one doesn't have a fancy high voltage capacitor checker?

Pictures of the caps in question:

   
   
   

Thanks for any input!