Jframe, per your question, the El Paso catalog shows the Austin as having a full back flap/belt loop and the retaining leather across the front. The Tom Threepersons is less bulky/simpler with a shorter belt loop.

Good luck in any decision you make.

By the way, the closest car I had to those years was my ‘66 red Wildcat convertible with very good dealer installed A/C. Nice car - and the 401 was a great runner. Went down the road quite a few years ago, but kept my low mileage ‘69 Coupe DeVille