The "Raison d'etre"..."reason for being", for the "premium" associated with the "T" SN is the belief...often "less than true", that the "T series" were fit and finished much better than "other" BHPs. Not to say that one shouldn't...simply because of downright foolishness in the market, expect to pay a "premium" just for the "T" SN...such is the silliness associated with the BHP marked of late.
With that said; this "T" appears to have had issues before the plating...perhaps that's why it was plated, and looks to have received less than stellar care once it was plated. And...market variations aside, I personally wouldn't pay more than $400 for it...not knowing what's really under the plating but knowing the costs, waits and hassle involved in attempting to return it to a reasonable semblance of its former glory.
FWIW, "Luftwaffe symbols"? That would be EXTREMELY rare, perhaps you mean the standard WWII German Waffenamt codes found on occupation manufactured BHPs; WaA613, WaA103 or WaA140 for Fabrique Nationale, Lüttich?