From the Wikipedia page on the Northrop T-38 Talon:
Most T-38s built were of the T-38A variant, but the USAF also had a small number of aircraft converted for weapons training (designated AT-38B), which were fitted with a gunsight and could carry a gunpod, rockets, or bombs on a centerline pylon. In 2015, 504 T-38s were still operational with the USAF, with many more in operation around the world.
What, if any, is the difference between these weapons training capable T-38B and an actual combat aircraft? Is there anything missing (intentionally or otherwise) on a T-38B that would render it ineffective for actual combat, or is this term "weapons training" merely a term used to describe a trainer aircraft? A trainer, due to its age and ineffectiveness against modern aircraft?
Could it be fair to compare some variants of the F-5 against the T-38B? I'd be interested to know the difference, since the F-5 is undoubtedly an actual combat aircraft and not a trainer.