64 instrument cluster swap into a 65 barracuda harness question

Most obvious difference I see, one has the mechanical inst' voltage limiter in a separate more common plug in can. ( That's the one where they put a board attach screw underneath the limiter. Foolish engineering in my opinion. ) anyway
The other panel has that limiter housed inside the fuel gauge. Whether that difference is relative to the extra wire difference or not, I can't say.