Bulova 1967 Commander
This was my grandfather's watch. The case it came in says President 23 Jewels, but the watch says 30 jewels. Someone wrote 1968 on the back of the owner's manual. Under the serial number I'm pretty sure it says m7 which should be 1967.
I have not opened up the watch and would rather not, but am curious what exactly it is.
On the back it says:
10 kt RGP BACK
Any help is appreciated.