military pocket watches

[2pounder]

I've inhereted a couple ofmilitary pocket watches, one marked 6E/50 which is RAF and one GS/TP which is army. two questions, the number below the markings. Is it the service mans number? Did the marines also get watches and if so were they naval issue? Did the Observer Corp get watches.
Any help appreciated. Thanks.

 

[LCplCombat]

Can't speak about RAF but the Army watches wern't issued to a man to keep, they were only a temporary issue and handed back to the QM when he left the unit. Hence the nickname G10 watch, shortened from G1098 which was the name of the stores account in the QMs