There is some changes to make with the GAZ 24 years. Some current model years are wrong. I'm basing this statement on this site dedicated to GAZ 24 and on my own researches.
http://gaz24.ru/c117592/?page_id=2026

- The indicators on the front fenders should be 1977+ instead of 1976+
(in my own researches I saw that none of the 1976 cars have these indicators, gaz24.ru stands for 1977+ too)

- The new bumpers with overriders should be 1979+ instead of 1977+
(gaz24.ru says these bumpers were introduced in december 1978, this information was in fact published in the magazine Za Rulem from November 1979)

- The new type of taillights with incorpored reflectors should be now 1980+ instead of 1979+
(gaz24.ru says middle of 1979 and knowing that there are some cars with new bumpers but with the old taillights and reflectors, better to set 1980 model year for the newer ones)

The other years are correct, nothing else to change.

you mean that all 76 should become 77, etc. ?
For all the 24-something?
i.e. in the list http://www.imcdb.org/search.php?resultsStyle=asList&sortBy=2&make=GAZ&model=24&modelMatch=- 1&modelInclModel=on

No, because there are something about the seatbelts too. I will do that manually.

The only thing that can be done automatically is 1977 to 1979. Because it will be a nightmare to do all them manually.

After that, I will check for errors and correct if needed.

Maybe you want to check the current 1979 that have to be changed to 1980 before that? Or else all the ex-1977 will be mixed with the currently-1979

Yes, maybe.

So do 1979 to 1980 before. I see they are too much.

ok, done