Very interesting. I wrote an article (unfortunately in French) dealing with these helmets. Most of them we can find today come from the battle of "Les Loges" near Roye in octobrer 1914, where hundreds of wounded "Colberger" were left after an attack on the french positions. French took lots of...
Yes, you should check the history of AR43. Some regiment histories explains clearly that they took helmets from others BA. For instance, RIR 234 took pickelhauben fron Guard, Pionnier and even police.