Anything can be done. The question is always, how good are you at fabrication, and has your mother ever had you checked for sanity, and what were the results?

Why not sell the 54 cab and buy an earlier cab? I have replaced a 52 dash and it was a major PIA. I can only imagine the problems putting the earlier dash in a later cab. BTW, if I had to do it over, I would have scrapped the 52 cab and looked for a better one to start with.
Carl