Mag catch out of spec - KAK Industry Lower Parts Kit, For AR-15, Black

After reading the other reviews I thought I’d take a chance because the price was right. The good news was the kit was complete, all the pins and springs were included as was the grip screw and lock washer. The bad news was the magazine catch is out of spec, it looks like the part was never finish-machined but just parkerized along with the rest of the parts. Finish is a sort of brown black, doesn’t match the receiver but for my cheap truck gun I don’t care - I guess if rusts I’ll have to replace the hold open (of course I bought a different mag catch already.)