I believe that watch is 1979 Accutron Date & Day "G"
EDIT: by manufacture date of movement fixed production year to 1970, watch have wrong caseback
Nice watch and good ad match.
I agree 1979 Accutron Date & Day "G"
Very nice Accutron; is there any way to date the movement? This watch should have a 14KT caseback, at least the early 70s ones did:
Is this really a base metal case from 1979 or one from earlier in the decade with wrong caseback?
In reply to Very nice Accutron; is there by Andersok
with wrong caseback you're probably right on movement is date stamp N0, good eyes Ken :)

aha....is that why the price is $195? Good eye Ken.
I would say it is an Accutron Day & Date. I'm not sure about it being a G variant though. Jaroslav, have you tested the rest of the case, is it 14K solid? It seems unusual that the back would have been swapped out.
Geoff, I have not tested it, but I'll do it
so today I did a probe on the inside of watch case and test it with acid for 14CT gold, the result is positive,
but it is interesting that the attached advert does not mention the case material, I saw the same model but with 14k GF case, not only solid gold, it is possible that the same model was produced with various case materials
there is attached model with 14k GF case, the sale takes place just at auction
In reply to so today I did a probe on the by jabs
This 1972 ad mentions 14KT GF case

There are ads for the silver or white dial as the "F" which also uses 14KT GF

J, you have N6 on the case back, and N0 overstamped with what looks like an overstamped '6' on the movement.
Maybe in 1976 the case back was s/s, not gold. The price of $195 is not indicative of solid gold, 1969 prices of gold cased Accutrons are from $250-up. Ordinary steel/gp watches from $140-$200+, Accuquartz prices started at $250 in 1973 for non-solid gold!
I guess I'm back to Day and Date "G" based on the ads above. In terms of the year, I say stay with 1970.