I also think the pictured item is a Burn1. Yes, you should be able to read and write the 27SF512 chips with the proper address.

I'm not certain on this but without knowing what the 27C128 chip is programmed for you may have to open the hex editor to see whats om there but that's not going to tell you anything, at least I don't have a clue how to read it. You could just do a "Blank Check" with the Moates PROM I/O utility, that would verify is anything was actually on them. You can also expose the chips to Sunlight for a few days to erase them.