The 7FB is a serial number prefix, it was the most common B model. Like the 4CK, 3ZJ, 8PN, etc… The main differences between the B models and C models were the wider rod bearings of the C for better durability, ATAC as opposed to Jacket Water, and some timing advance and injection pump changes. There were also some other changes, I think the nozzles went to a higher VOP.
I have done hundreds of injection pump, governor, timing advance rebuilds and set them up statically and then graphed the timing advance curve adjusting the start and stop and total advance to a half of a degree. I normally go 10% or slightly more on the fuel settings and put the advance right at the top of Caterpillars spec for the specific engine serial number and performance spec number. That way you will get the most power out of the engine but not have to worry about melting / cracking a piston as long as the driver isn’t and idiot and keeps an eye on his EGT.
I left my Cat dealer almost 8 years ago to go work on Yachts and make some more money and work for a close friend. My kids graduated high school last spring so we sold our house and are building in a different state, so to make that happen I left the boat yard (working much less) and went back to the Cat dealer while the house is being built. I have been blown away by the lack of knowledge of the old product at the dealer! It seems like you are correct, no one knows how to work on mechanical fuel systems anymore. Crazy stuff!