When you say it doesn't fit the Gibson, do you mean shape or screw locations? If it's just the screw locations then as long as it covers the existing holes, it's not that big of a deal to make a few extra holes under the PG that no one will see with either PG mounted.
ok proper.
If it were just the holes, I'd make it work. The size is wrong. The Gibson body is larger than the Epiphone.

