Alex Sepkus - hallmarks?

[Circe]

Hey, guys - I just got an Alex Sepkus Circle Band off of eBay (I am disgustingly smug about this: the seller just listed it as a "vintage band" and charged accordingly, and I recognized it from the blurry photos alone!), and I''m mentally authenticating it. It damned well looks like the real thing to me, but somewhere along the way, someone polished the inside of the ring a tad too enthusiastically - sizing? removing an inscription? - and managed to just about remove the hallmarks. The outline of a now-blurry PLAT is still visible, but there''s another sign I can''t make out. It''s either a series of numbers - registration or serial #? - or something else that''s been so vigorously polished that I just can''t recognize it without a hint. Alex Sepkus owners, what''s in your rings?

 

[Circe]

Bueller, Bueller, anybody, Bueller? Perhaps I should ask over in Jewelry ... but if anybody wants to volunteer in the meantime, I will be v. grateful!