Thank you for providing the pics! Definitely a post 2009 SPFX in manufacture as his castings before that general time didn't have the ring arrangement it was just the plain top of the facemask with the three tabs. That casting flaw that runs down/across the front of the ring and fillet is a tell for his work (I've seen several in hand with that flaw). You'll have to forgive me as my memory is somewhat vague about when the ring was added to his castings, and there isn't generally a lot of conversation around his castings because of his reputation, but I have a photo in my collection dated June of 2009 which shows the ring in place. I had an SPFX ANH helmet that I bought from a fellow RPF member back in 2005ish from an earlier generation where he had modified the dome to have a shorter "skirt" to it (this was based on a general misinterpretation of photos).
Cheers!
Dave C