Not me. I would leave it as is. Adding a liner would add no value IMHO. I'm the type that leaves every thing untouched. It should display fine as is.
My greatest fear is that one day I will die and my wife will sell my guns for what I told her I paid for them
"Don't tell me these are investments if you never intend to sell anything" (Quote: Wife)
I guess it depends on the type of collector you are. If you don't mind something that has been messed with, and since you know the source of the change on this one (hint: it's you), and considering adding a liner doesn't require you to modify or damage what you currently have, it's not going to hurt the helmet to have a liner. It might be tricky to find a proper size and condition liner. But, like MAP says, it's probably not going to add much value if any since there's no getting around the fact collectors prefer all original items.
I would add though, if you sell it, and the next guy sells it and so on, at some point some poor fellow is going to be given the "my grandfather brought this back just like it is" story about how it's all original and worth twice what it really is worth because of all that sweet "battle damage". Serious collectors can tell when they've been messed with, but lots of buyers don't know original from a cooking pot. So, in a way, there's a lot to be said about leaving things as they are so that you preserve the historical context the item has. Once you add stuff or change things, it just becomes another helmet.
"Only a real risk tests the reality of a belief." - C.S. Lewis
If I were a collector, I would definitely be of the "purist" mindset. I'm not a collector (and by extent, seller) so adding the liner would not be to hoodwink a buyer or make the helmet something it is not, but I do see your point. After I'm dead and gone, the completed helmet would take on a life of its own as a complete piece.
My intention would be to complete the helmet for myself and any friends I showed it to. Before I started investigating its origins, I had no concept as to how it was supported on a man's head. I like the engineering angle as well as the functional use so the liner paints a clearer picture of the helmet's purpose to a novice.
As far as finding one goes, another thread on this forum is of an exact fit for this Q64. It isn't for sale, but seeing it inspired me to ask the question.
Out of respect for the man who wore this helmet in battle, I will not retrofit another man's head liner into it.
Thanks for all the insight on its history.
Last edited by icarus; 02-20-2016 at 11:40 PM. Reason: to clarify my position
It's a nice helmet. Good color and excellent decal, not worth a mint but a nice first helmet.
Could there be a possibility that its is period shrapnel damage?