Our Buyer’s guide to vintage Fender amps explains in detail how you can date your amp by looking at serial numbers, tube charts, transformer codes, speaker codes, Fender logo, etc.
Lots of different speakers were used in the blackface and silverface era Fender amps. In a BF Vibrolux Reverbs you could have either Jensen, CTS or Oxford, the BF Super Reverbs had Jensen, CTS, Oxford or sometimes JBL, the BF Pro Reverb had Jensen, Oxford or Utah, ++. In the silverface era Eminence, Oxford, Utah and Rola were more often used and Jensen was phased out. Even at fenderguru.com we struggle with keeping a correct amp and speaker model overview. There are also exceptions to the rules where Fender delivered non-standard speakers in special orders, Christmas campaigns etc. It’s complicated….
See our Buyer’s guide to vintage Fender amps for a guide and picture gallery of the known original speakers in the blackface and silverface amps. You may compare these with your own speakers to determine what you have.