USP marking question

[bhale187]

With the slide removed looking down on the recevier from the top, just in front of the mag well my s/s USPF 40 has 10 or IO engraved surrounded by a circle.

On my P30L and P2000sk the date code is engraved in this same spot.

I'm curious as to the marking's meaning because it is a KH code USP.

[cueist]

Until the last couple of years the Frames, and Magazines were Dated Coded differently from the Slides on the polymer guns.

[bhale187]

ok, thanks

[T.Smith]

Mine is a 2008 usp compact, and my slide is obviously date coded at AI, but when removing the slide, the frame is date coded as being AH.