Hi,
I have several of the Hammond units here - they are "The Mutts Nuts"
But are valve driven, and recovered..
I seem to remember that Fender were the first amps to feature "Hammond Reverb"
It took quite a few years for other makers to clone these tanks, the most famous one being Accutronics.
Actually the reverb spring unit is mounted on 4 springs anyway so even bolting the outer carrier direct to the cab
should not cause problems..
The earlier reverb unit used by Hammond was this one:-
Used in Hammond PR20 and 40 tone cabinets, the 3 springs give a full rich reverb, but if the cab is knocked they make a hell of a noise...
The PR40 is a 3 channel amp using 6 EL84's givin an overall power of 40 watts.