National were not the only ones with EPR on the DC10. SAS also had EPR on theirs, although N1 was the primary parameter. Might have been the same on other KSSU DC10's as well.
All the KSSU DC-10's (vertical scale gages) had a common cockpit including EPR IIRC. But EPR was often neglected because it had no operational use.
ATLAS ships had steam gages, with N1 at the top of the engine stack and EPR at the bottom (if it was installed at all...). National was unique for CF6-powered DC-10's in that EPR was used for power mgmt. and was at the top of the stack.
Can't speak for DC-10-40's, but with JT9's I'm sure they were pwr. managed by EPR...