What was it?

Last week I walked up to a couple pilots discussing an airplane that was
sitting on the ramp at STE. They noted that it did not have a data tag on
it so they really weren't sure what it was.

What it looked like was an early straight leg 172 fastback, but it had a
swept tail, not a straight tail. Beautiful airplane but nobody had heard of
a swept tail fastback. Was there such a beast? or did somebody put a new
tail on an old airplane?

Any ideas or answers appreciated.

Jim