A 1964 Fender Concert is a collectible amp, there is no way I would mod that amp. It will ruin the value of the amp and you may or may NOT like it after the mods.
If you don't like the amp I'm sure you could find someone to buy it or trade you an amp with reverb maybe a Super Reverb for it.
I'd just get a good reverb pedal or a tube style Fender Reverb unit if you HAVE to have reverb with that amp.
A clean 63 Concert just sold on eBay for $1450, which still seems cheap to me for that kind of amp