I've never seen such a modification before either. In this case it's swapping two address lines.
No idea why you'd need to do this. Assuming they're correct ROMs, this would make data appear at incorrect addresses.
If this modification has been like this from new, then at a guess it's to correct a problem if those data lines in the ROM had been accidentally swapped during a prototype manufacturing run from the ROM manufacturer??
If this is the case and the rest of the computer is standard, then the 3.1 ROMs should work.
Hard to tell from the photos, but it looks like the wire is only soldered to the socket's outer contact, meaning that if you cut off the wire flush at the soldered joint, the 3.1 ROM should still plug in and work normally.
