After the Christie’s auction that introduced the community to AA/SDS almost 25 years ago, I actually visited SDS while vacationing in England around 2003ish. This was well before his fall from grace occurred.
If this is the helmet with the corrugated rear lower tube (I can’t tell), the story he told me at the time was that these helmets were supposedly prototypes for ESB (not ANH). I do not know if he was solicited by someone associated with the production to do this, but his goal originally was get rid of the ears and make changes to the top/back to allow easier removal from the buck. He said his idea didn’t really work out because the corrugated hose wouldn’t last under the heat. Ultimately it was never adopted.
Again, I’m not sure if he did this on a whim or there was an ask of some sort. The way AA has conducted himself over the years, at this point I’m not sure you can believe anything he says. Provable fabrications have a way of ruining your word.