You may want to try your local Ford Dealer and see if the parts are still available through Ford. I bought a set for my 94 Cobra back in 2005 and here is the actual Ford Part info below for you to reference while at the Ford Dealer.
The correct Ford Part #'s for the 94-95 Mustang factory (-) & (+) battery terminal covers:
F3LZ-14277-DA (I think this one was the positive +)
F3LZ-14277-EA (I think this one was the negative -)
I hope the above was helpful to many others as well...