The reason why I think these are off.001 or so is because I have shimmed two guns with quality shim material from a machine shop. If I remember correctly one took only .001 and the other may have taken .002. The shims were attached using Loctite retaining compound and pressure. These guns are in service now, although I sold one of them.
I have a gunsmith who actually welds the hook and stones down to fit and finish. I have had two guns with welded hooks (You can't tell they've been welded). This is what I would propose to do on the next gun I have tightened.
All this said, I just checked the barrel to face and cannot fit a 0.001 feeler gauge between them with the forends off. Looks like I will just shoot these for a while. Thanks for reading! Mike