That is a nice car for a good price, I never worry about the MPG on a car I pay less than $5000 for. In my opinion you can buy a lot of gas for the extra expense of a more modern car. And by the late 70's the MPG had come up to the high teens on most of these cars, my 78 Impala wagon in stock form gets 17 combined, and over 19 on the highway. That is only slightly worse than my 2012 F-150 with the Ecco Boost engine.
If I had the cash, I would be after this one. The 2 door is very much not common, and this one is in terrific condition. I could even get used to the "Cordovan" paint and interior. The price seems quite reasonable, too. Swap in an AOD in place of the 3 speed auto, and the highway mileage will not be too bad, either.