What a tangled web we weave, when first we try and decipher Manurhin and Walther serial numbers. Having said that. All of the Walther PP's,PPK's, regardless of what is roll marked on the slide were manufactured by Manurhin from 1952 until 1984 when Walther started producing the guns again ( until 1989 ) At the same time Manurhin also sold the guns ( made under license by Walther ) under their own name. In fact if James Bond had been a real person, M-16 would have issued him a Manurhin PPK in lieu of a Walther. ( British intelligence bought a number of Manurhins ), they also sold a batch to the German police , go figure. Yours is a Manurhin made and sold under their name, Serial number 14,114was made about 1953, yours serial number 138XX would have been made about the same time. We have a Walther collector, Danny, who stops by ever so often, if I'm in error then he will have the correct information. Hope that helps,
By the way, some where along the way the Manurhin grips were replaced with Walther grips .