Dav you may be right..It was a very big cab anyway and could have even been late 60's or early 70's and now I think about it could have been the really large 2x15 cab. Either way I couldnt get it into the boot (trunk) of my car and it was a large boot as well. I had a look at some Fender cabs of the 60's after your correction and the '69 Fender Bassman 2x15 looks just like the one.I don't think they made a 4x10 cab for the bassman in the 60s.
Edit your profile.
Vintage late 1960s Fender Bassman 2x15" cabinet - JBL D140F, w/ cover
Hey Dav..my memory is pretty chronic these days as i'm 66 ya know loll..thanks for making me look it up..it really was a big beast though lol
Another reason why Fender Rumbles are so popular is that they have been designed to sound good at 0 cut/boost. Set controls at noon for signature Fender tone. No you're not flat, but you will sound good! 