question US Service SGT's

[Bennett]

My son aquired a revolver with this wording under
the Smith&Wesson on the barrel.

Can anyone tell me about this particular item.
Is it a special production for a US Law Enforcement agency?
If not what would that wording mean?

Thank You for your assistance
b

 

[BUFF]

Look closer, it's probably "U.S. SERVICE CTG." CTG is short for "cartridge" in S&W barrel marking nomenclature.