Question about sons helmet...

I have seen many helmets both ESB and ROTJ with a curved visor at the chin. I have also seen many with it being straight?? Which is the correct visor shape?

I'm not the ultimate authority on this (there's probably somebody with MOM photos, at least), but in Star Wars Chronicles you can see the ESB visor really clearly, and it's curved right down the center. I've copied that visor, but I don't know about the other versions for sure.

RotJ Helmet:

(Thanks Brak's) So the ROTJ visor had a very slight curve to it... Any shots of the ESB helmet out there?? And whats up with those mounting pins?? Anybody ever find those to secure the visor??

As requested, ESB:

Wow, you ask and you shall receive on the TDH! THANKS a lot Brak's, I appreciate it... Question answered! Anyone have an idea about those visor mounting studs???

I can't seem to find the pic at the moment, but it seems the mounting brackets were added to the completed helmet with some sort of *epoxy* spread on the inside.

*Edited after being schooled in adhesive compounds.*

Epoxy