Hallmark on old sterling buckle

[wwwamericana]

Was wondering if any of y’all could help me in identifying this hallmark on the back of old buckle.
I am including two pics of the stamp but I may even have it upside down so please stand on your heads if you think that’s the case. Just can’t figure out if it lettering or a symbol. Your valuable assistance is always greatly appreciated.

[Ravenscry]

Would you mind sharing a photo of the front of the buckle?

[wwwamericana]

Can do - should have done that in my original post.

[wwwamericana]

Where is everybody? This hallmark is driving me crazy!

[Ziacat]

It’s just possible no one can find anything on it. It may remain an unknown. Possible it’s not native.

[wwwamericana]

Now that’s a thought…
Thank you, Z!