Will any of the Pre-64 Winchester scope mounts fit the Dakota 76 action or will some block the bolt release? I'd like to put Warne style bases on mine.

Someone may correct me, but the PRE64 bases won’t work, but the bases for the Classic will.

From my experience the rear base screw holes are spaced differently. This was a Dakota from the early 90s.

I have two, both 76s in .338wm, they do accept P-64 MAGNUM bases from Talley's which require standard QD rings. I prefer the extended bases and medium rings as I have a "Neanderthal" neck and bulky shoulders.