I've bought about 10 of those visors from swfladoug in the past.
They are "THICK" Rigid Lexan. That's why they're so stiff. The thickness of these visors is actually extremely accurate, however, the color is far from. His are usually very black, to dark smoke. No green. I think I still have 4 or 5 of them. To conform the visor to the inside of the helmet, a heavy duty hair dryer, or a heat gun (on LOW setting) works great. Some have even baked the visor in the oven. Very common. For those that want extremely thick visors for movie accuracy, you will have to do the same thing to them (if we ever find them in green that thick) 
He's a great guy though, if you contact him, and explain the situation, he will make it good. He always has with me.
Take Care