Sound like a good car to me but need pictures to full assess. I personally do not think that the 1980 TA is where it is at money and resale wise - although some on this side would disagree. I think the 1977-79 would hold better as long as it has the 6.6 liter Pontiac 400 or Olds 403 with the 400 being the better of the two. Of course the 70-73 is where the real money is at - and I think most on this site would agree.
But with that said, the car you listed looks like it has a lot going for (numbers matching, ws6, etc). Below are some links to help you in your research. If you have the option to choose, chose one in good shape, with a low production run, the Pontiac 400, with 4 speed, WS6 suspension package, and T-Tops.
Production numbers:
http://www.78ta.com/production.phpVIN decoding:
http://www.78ta.com/vin.phpCowl Tag Decoding:
http://www.78ta.com/cowl.phpAll of these links and more can be found from the homepage:
http://www.78ta.com/P.S. Don't let the low production numbers on 1980-81 fool you. Once Pontiac stopped offering the 6.6 liter and went to a smaller engine the public lost interest. They just were not as desirable cars as they were the year before and sales tanked. If you get an 80 or 81 make sure it has the turbo otherwise it will probably never be worth as much as those from 1970-1979 with the 6.6L.
Good luck in your search. I hope you find one that makes you happy. I know you could never pry the 1979 I have from my hands. I love these cars.