Yes, it does! All v3 rumbles got the same preamp sections from r40 and up. Heads included. The only difference for the 40 is the lack of send/return.
Not the stage800 and studio40, those are digital modelling ones.
If the controls looks identical to Your r100, it will be the exact same preamp section.
Also You can use any rumbles (r100 and up) as a "main preamp" and daisy chain them via send/return.
https://reverb.com/item/45676316-fender-rumble-500-bass-head
Edit: the r500 is an excellent value combo, can do 350Watts alone, 500Watts with an external cab. Or You can chain it to Your r100 for a 450W 1*12+2*10 or 600W 1*12+2*10+2*12 dual-powered stack!
Just watch out for the impedance, the 500 combo needs an 8Ohm ext. cab.
Another option are the head(s), sadly the 200/500 are discontinued.