Yes you'd have to combine the files if you want to do it with unidasm.

I'd just use MAME:
mame.exe feagv7 -debug
(inside debugger) dasm feagv7.txt,0,20000

As I said, I haven't checked it myself, but just a cautionary note: there's a good chance the bytes are not program, but data (some table, or opening book), which makes it more difficult to check.
But IMO the file comparisons were enough to determine which one was a bad dump.