Okay, that's the revision number for the latest Power Macintosh 8600 Enhanced, which uses the Mach V PPC604EV cards. It should definitely have support for 128MB DIMMs. It's pretty unlikely that someone would have slipped an 8500 into an 8600 case, as it also involves changing the power supply. There's not much different between the 8500 logic board and the original (Un-Enhanced) PM8600 logic board except that the power supply connector changed. The ROM also bumped up from 28F2 to 34F1 but I've never seen any tangible evidence that the ROM revision makes a different.
But the 8600 Enhanced has the 34F5. So you have the latest and greatest.
Next, can you do a detailed scan of your DIMMs front and back? We need to be able to read the writing on the actual chips. Most of the chips will be identical, so if you prefer, you could just count the chips and read off the model numbers for us, instead of providing an image. This will allow us to identify the memory chips and their capacity (probably) and then multiply by the number of chip, in order to determine the actual capacity of the DIMMs.
If there really is 128 MB worth of RAM chips on those DIMMs then that will be puzzling.