Without a doubt - the helmet is legitimate and true to all points made by Mike.
I was the previous owner, and having held the helmet in hand (very carefully and only on occasion), there us no doubt the net is original, the mud over the insignia is original, the liner us original to the helmet, the chinstraps are original to the helmet, and the partial laundry number is in fact Humphries.
This is the second 3/116 helmet that I have viewed that did not have a painted liner, so that part is not a concern. As mentioned earlier, the 29th was meticulous at marking helmets (unit insignia), gear (full name, full ASN, Laundry Number, and partial Laundry Numbers), and uniforms (SSI patched M41, Tanker, Wool Shirts) prior to the Invasion of Normandy.
Almost all surviving examples of found (and legible) equipment and uniforms are marked and named; which is also a word of caution as the forgers have taken to the same.
The 29th also kept meticulous morning reports starting on June 8 (or at least those that have been collected and consolidated). This makes 29th identification relatively easy as their consolidated and open source records are thought to be about 90% complete, far better than almost any unit. We were able to scour the records, coupled with the documented location the helmet was found, records indicating injury and plausible cause for the lost helmet, the partial laundry number, to ensure I was as accurate as possible in my description of this wonderful time capsule.
I have also seen and owned a few documented 29th items that were identified, AND marked with a partial laundry number. It is not common, but seen from time to time and particular with soldiers in the 29th.
Take in the research Mike has provided, documented and compelling research, as well as similarities in other marked, and named 29th items, and you are left with an undeniable helmet.
Mike needs not prove the legitimacy to anyone. It all speaks for itself.
The helmet is missed, but in better hands. Well done again, Mike.