I used to own a stainless full size USP45 date code KK. The barrel appeared had a standard looking blued dull finish that wore like most finishes. My new Tac has a different finish on the barrel. It's like a thick coating that starts out somewhat glossy and then wears to a flat black with some areas wearing down to shiny metal. The gun was purchased brand new and now has about 400 rnds through it. Did HK change their finishes?