I do have a file but absolutely no idea if it's any good. Any way (other than burning and trying) to verify?

Do any of the pinmame / virtual pin emulators that are about try to use the original rom files?  I think they do, but  I've never used any of them but this might be a way to test. Someone on this forum who plays with the emulators should be able to comment.  I guess you'd also need the ears to know what the original is meant to sound like.