A bandmate had a Twin that had a JBL on one side and a Fender in the other. Guess the original owner could only afford the one JBL . Might have been an upgrade or they blew the original. It was in the 80's so guess the amp was late 70's or early 80's. Anyway there was a subtul differance in each speaker and we thought this was a cool mod.
Best thing about that amp was we found a Mutron Mirco V down in the bottom that I still have. The bandmate who had bought the amp gave it to me thinking it was some piece of junk.