I wasn't saying that the VF-1D was a trainer just because it had a "D" desiganation, what I was saying is that all of those aircraft are trainers, but are perfectly capable of loading up with ammunition and missles and fighting.
Hence the Mentioning of the F/A-18B/D, the F-5/T-38 and the F-15B/D all are trainers that can function like thhey're combatant counterparts in the case of the F/A-18D the Marine Corps uses it as a night attack aircraft and the F-15E was developed from testing either an F-15B or D airframe.