I'm leaning towards a Grand Record. As you point out, the bicycle should be pre-1979 by virtue of the top tube's cable clips. Also, of the three 1979 models using Vitus 172, only the Grand record has that decal scheme. I just happen to have a pics and specs for a 1978 Grand Touring and Grand Record (but no Grand Jubilee) and only the Grand Record uses that scheme, but it is still using cable tunnels, has bottle bosses and uses Cyclone derailleurs, so yours should pre-date that. It used Vitus 173 and those side-pull, Weinmann brakes. Your rear derailleur appears to be a Huret Eco, which came out in 1976. So, assuming it is original (are the shifters and front derailleur Huret?) and pending further evidence, the most likley candidate would appear to be a 1976 or 1977 Grand Record.