Brent,
Though I have an original-style seat in my '66 I think your options are numerous. But I wouldn't get too caught up into having to have the seat fit the original mount points. It's not a big deal at all to drill out a couple pair of new holes for new seats. My low powered Makita was able to chew through the old sheet metal in less than 10 seconds when I drilled holes for my new shifter boot. You can either have the original holes welded in or just put the old hardware back as filler placeholders.
-ftyler
