Hamilton driving watch from the late 30s? or 40s?

I know I know the band is ALL wrong for it ,.need to get a nice oiled leather soft band for it but till then its wearable,..and hey it was 5 bucks at a garage sale!! ticks along well ,..face a litle scratched up but its 80 pluss years old n still running!! nice gold filled case,..cant figure out how it opens and dont want to scratch it up so no sexy movement pic ,..besides my cam only goes down to 18 size PW movements without gettign all fuzzy bad