I’m curious. On what are you basing this statement? Have you measured the distance between the nut and fret 12 and compared to the distance between fret 12 and bridge. If the fret 12 to bridge distance is shorter, or perfectly equal to the first measurement, then you are in trouble. Having that said, I really doubt that the quality control of Epiphone would miss THAT big fault. I think that the problem might be another.
If the problem is that the saddles in the bridge is adjusted as far back as they go, and your intonation on fret 12 is still sharp, it can be a completely different problem. You write that the guitar has a “nasty bow”. If this means that the string height is extremely high, that will also affect the intonation. Intonation is used to compensate for the extra tension on the strings caused by pressing it down to the frets, stretching the string slightly. Higher strings means that the saddles need to be adjusted further back. Very worn frets might also cause offsets in the tuning. A string is supposed to rest on the top of the fret. If the fret is worn fret the break off point is moved towards the bridge. This also means that the intonation will be off. If you still have the old strings on that guitar you will also have problems with intonation. We have several treads in here describing the problems with intonation a guitar with old strings on.
So, before you start to adjust intonation, you need to adjust the truss rod, adjust string height, level the frets, and put on new strings. There in NO WAY that you can intonate before you have done those things.
But if the length from fret 12 to the bridge is shorter than from the nut to fret 12 you have to move the bridge.