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.
Instead, there were approximately 2000 of these chasses produced, which then ended up as one of the three models in question.
Dating an amplifier by serial numbers can be effective as well.
Again, it's important to be sure the parts are original on the music equipment to get a valid date for the amp.
Black and White wires terminated in 1/4 inch push on terminals.
Green wire terminated in screw terminal for ground connection to chassis.