Reusing an old receiver can be a fun project, as long as you keep an open mind about what you are getting into. Copying someone's modification, on the other hand, can be an exercise in frustration, as there is no guarantee that the insides of what you buy will be anything like what someone else bought. Circuits are constantly redesigned these days, so buying two from the same Ebay seller is no guarantee that both units will be identical.
Zack W1VT