No Humor Man wrote:
It is still unknown whether the extension was done when the screen used ANH was originally molded, or if it was added later to a casting from that UK mold and then remolded and used for the ESB helmets. My personal view is that it was done when the ANH was molded, since it was likely done with clay - that was removable and not permanent - similar to the filled in chin vent and the filler around the lens corners, but we simply don't know. We do know however that it seems to be a feature on several helmets cast for ESB and some tour helmets.
The TM isn't the only helmet in fandom that has the neck extension. The VP also had it but was trimmed off by the owner before making casts available. Another cast that was shown off here on the forum some time ago also has the neck extension, but that one was longer and trimmed strangely, so, it is not an uncommon feature.
Clearly there wasn't an extension on the original ANH. Brian Muir would have mentioned it. He and I discussed the mask at some length when I showed him mine, particularly how it was shaped in the neck to meet with the armor. He made no mention of any kind of neck extension. It's an ESB only trait.