RB67 WLF on GS-1?

I hope this is not too stupid a question.

I've been looking for some time for a WLF for my Bronica GS-1, but they are rare and ridiculously expensive. (I've even gone so far as to fashion one out of cardboard, with surprisingly good results... well, adequate, anyway ) I have an opportunity to pick up an RB67 finder for a fraction of the cost of the Bronica. What are the chances that this would fit or could be adapted to fit my GS-1?

Cheers,