Bulova 1927 Ambassador

This watch was my great grandfather's. I plan to have it cleaned up and restored.  The outside of the case only has letters on the side "GF".  Inside of the case reads: "Bulova, 14K, Gold Filled, American Standard, ?Pat Jan 1921, 7281700."    There is some pencil writing inside the case as well, apologies, my camera can't pick it up and I haven't quite been able to decipher it.  I assumed it was from the 1920s, based on other 'unknowns' I've seen posted and also the 1924 advertisement I uploaded (it is a close but not perfect match).