Mark--
I don't agree that the military contractor helmets were used by the fraternial groups. I wrote an article for my MilitarySunHelmets.com site about it:
http://www.militarysunhelmets.com/2012/lodge-hats-army-surplus-and-the-bannerman-catalog" onclick="window.open(this.href);return false;
Here is the problem with this line of thinking... the Odd Fellows (as well as other group's) have helmets that don't in any way appear to be military. The shells are covered in calico drill cloth, not the canvas that is used on the military helmets. The bodies aren't typically cork but other materials including a fiberboard material. And the liners and linings are completely different. So I don't think most of the Odd Fellows' helmets were military that wasn't utilized.
That said I think that Bannerman did sell the parts, including teh spikes, spike bases, chinchains and those accourtments were used. Likewise, I think Bannerman bought up the helmets and they were in storage.
I first bought sun helmets when I was 12 years old - so 1980. I found several Odd Fellow helmets I thought at the time were military. Boy was I disappointed later. But since that time I've done a lot of research on these. What I find more interesting is that 30 years ago it was impossible to find an American white summer helmet.
Then 10 years ago they started showing up. Someone clearly found a cache of these. Now these are quite common, even if the ones in good shape are harder to find!