The gains were all verified against actual amps. You may need to turn the master down a bit as there is slightly more level out of the preamp into the power amp. If you had the master at 10 before you will want to put it around 9 and so on.
The preamp gains on the Fenders did NOT change. They have always been spot-on and verified against actual amps.
Then the taper must have changed quite a bit?