To the best of my knowledge HK has never imported the patrol HG into the US.
The ones of which I am aware came out of Germany direct to US consumers via two German retailers. This goes for the older quad rail version(s) (yes there are two of them) and the newer MR308/G28 HKey version (which is what I have). Yes, I really like the fit and feel of it.
RKSUSA advertises them, but OOS. While I’ve had no issues with RKSUSA with the three or four times I’ve ordered from them, I have recently heard from a member who is still awaiting an order or a refund. I do not know the specifics. But I ordered a Michael Burk MR308/417 AGB last month and I received it within two weeks and it’s as advertised.
If you want one, I think your best bet is looking for a European Retailer who will sell and ship to the US. Mine came from German Gun Works and imported legally. Not sure if they have any or if they will still file BAFA and ship abroad.
Best of Luck.