I recall about 10 years ago, seeing a car very much like this in the same colour scheme (with non-padded burgundy vinyl top).  At the time it looked like a mint, untouched original car.  I can only assume this is the same one.

https://www.kijiji.ca/v-classic-cars/bedford/1977-pontiac-grand-lemans/1355821359?enableSearchNavigationFlag=true

1977 Pontiac grand lemans

$17,500.00

Selling my 1977 Pontiac grand lemans. Not to many of these alive original motor transmission frame mint 43000 miles. Little hole in front floor driver side and interior is decent could use new carpet smokes a little when first start other than that she is awesome drive like a dream I have these rims 22. And i have original rims and hubcaps. Ill sell with the 22 rims or without original rims has tires my asking price is 17,500 obo negotiable or trade for 2010 or newer 4x4 truck 4door with plow dodge or chev gmc must see no low ballers but make me and offer thanks