The McKaig=Hatch 11" Adj. is not verified as a Ford-purchase for the GPW.
Having said that, we don't have much info that is DEFINITIVE and the best clue so far is the Bizal late-war tool kit which has a MOORE in it. We do know that MH was a prewar supplier to Ford and that is worthy of SOME consideration, but many tool companies that supplies Ford in the prewar years are not guaranteed to have been suppliers to them (at least for the GPW) and accepted by the g503 so as was mentioned, it has no REAL link to the GPW beyond the MH/Ford prewar connection.
I believe that Jim Gilmore made the BHM connection to Ford tool kits but that was for 1 1/2 ton trucks so you have to take that connection at that value also.
The fact that the number of 11' MHs we know of is....probably counted on less digits than most people have...kind of says that they were NOT used in GPWs or at least not in any quantity it would seem.
I think at this point in time the "matching" mfger concept of tool kits has been less and less accepted, bar the five wrenches being from ONE company. The MH pliers design is pretty cheesy compared to Danielson and others and would have been CHEAP and that would have been fine for Henry's prewar car tool kits so it is a decent choice for a GPW kit.
I'd say that if you did not have a MOORE for the kit which has a better pedigree, then the MH would be another choice similar to your Fire Extinguisher which you chose just to mess with the Ford owners heads. Luca's investigation into the possibility of dating the 11" Adj by the characteristics of the OPEN handle or OPEN head GROOVE is one that is interesting and may very well be correct, but we just don't have enough data to confimr that, I myself am following that concept but it may only be correct for a particular mfger and not have the same dates of change for other mgers. Still, it holds promise to aid in dating each mfgers' 11" Adj.
As for the 8" Adj. I would think the link to Barcalo via the wrenches would be a better choice than Crescent Tool Company for a GPW. (see Roger's pic as that style is probably a winner!)
Here is the layout of the tag from the Bizel kit:

- John_Bizals_Spare_Parts-Tool_Kit_Photos_3.jpg (85.79 KiB) Viewed 479 times
PS...there are some repops of this tag with an incorrect layout/font, etc.!