That's all Glock will tell me when I gave them the 2 letter 4 number followed by PD serial number on newly purchased G22 40 police trade in. But here's the thing it has the "Frying Pan" Tennifer finish. I was not aware of Glock using that finish on Gen 4's. Any info by you guys with a whole lot more experience than me would be appreciated also the serial number is IMxxxxPD if anyone knows what agency that the IM is code for. Thanks you for any help you can give. As a side note I couldn't pass up a night sighted(still very bright) Gen 4 G22 still in the case with 3 mags and backstraps that were still in the plastic all for 275.00 have put 250 rounds through it not a hiccup as to be expected.