The shown movement was produced after 1949/50 as from this time the shock protection system has been installed. The dedication engraving from 1946 does not necessarily mean that the watch was presented this year. The nickel-plated or rhodium-plated movement has got a nice stripe damaskeened.
Another example of a Junghans J80; Junghans 680.72, this time with grained and gilt movement and a case diameter of 36.2 mm.
Again, I find it difficult in some caliber allocation. With the above list I tried to provide some clarity on the different caliber and their designations.
The movements were produced at the same time with or without divided wheel bridge. There are versions with 7, 11, 13, 15, 16 and 17 jewels.
There's caliber Junghans J80 with various imprints on the bridge: J80S; J80M (was probably Meister).