US Major Shoulder Rank Hallmark Question ID??

[Travd3]

Has anyone seen this hallmark before?  Its a first on me.

[Travd3]

Its a matching set and they both have the same hallmark. 

[Travd3]

Any ideas, suggestions, etc?  There are no other faint markings anywhere that I can find.

[Travd3]

Anyone have an idea? 

[S.ChrisKelly]

This is a selection of major's insignia acquired all at once.  Rough guess on the era is 1955 -1965.  Unfortunately, no leads on the "X" hallmark...  Likely unofficial.  The lieutenant colonel's insignia is simply marked "sterling" and is included for comparative reference.  It is also likely a 1955 - 1965 production.