I am not sure that the pathfinders did mark their helmets at all, though someone more knowledgeable on the Airborne may be able to help you more.
Pathfinders were volunteers from different units, they didn't have their own insignia they had the insignia of the unit they came from no matter which Div 101st or 82nd. However there were specialists who had different insignia...engineers, artillerymen.
Show me a man who will jump out of an airplane, and I'll show you a man who will fight!
General James M. Gavin
CRY HAVOC AND LET LOOSE THE DOGS OF WAR
What is it with all the Pathfinder enquiries!?
Why not just be a normal soldier!?
Everyone wants to be the best, different or special?
So many more SS than Heer.
So many more airborne than pbi.
Now the sheen of airborne has worn thin you must go to the next elite level, 'pathfinders'.
aka the 'chairborne piefinders'
Plus AI did that article.
aka Stigroadie
AFRA
better by design
"Truth is a shining goddess, always veiled, always distant, never wholly approachable, but worthy of all the devotion of which the human spirit is capable. "
Well I suppose as not every pathfinder unit camoed their jumpsuits anyone with airborne gear can pass as a pathfinder. Plus it gives you the opportunity to carry as random gear as you want.
Rarity = popularity, especially in a collectors market. And that's the same reason I never got all the stickers for my He-man album!
Airborne, commandos, Paras, Rangers, SS, Fallschrmjager, they're more commonly armed with the sort of AEG's that are easily obtained (Mp40, M1A1, Sten, Mp44 etc) as is their webbing, uniforms etc. Making it an easy first impression.
If there was an entry level price Garand/K98/Nagant/Enfield available (£150-200) then I'm sure you'd see a lot more standard troops.
Fingers crossed eh? 
