The only mod on mine is the nut has been changed out by the original owner. I rewired an Epi ES-335 I have. It was a big improvement buy a real pain to do. Just at a glance it appears the dimension of the F hole openings on an Epi are a little larger than my Gibson.Exactly, it seems to be entirely built to '59 reissue specs except for the color and the decal on the back of the headstock. Mine has been modded with a new wiring harness with audio taper pots (a job I'll never do again; fishing a harness in and out the 'f' hole is no fun). I also added reflector cap knobs just because I like the looks better.
The Gibson 'f' holes are a tight squeeze, full size CTS pots just barely fit.The only mod on mine is the nut has been changed out by the original owner. I rewired an Epi ES-335 I have. It was a big improvement buy a real pain to do. Just at a glance it appears the dimension of the F hole openings on an Epi are a little larger than my Gibson.