Helmstetter, like a lot of cue makers, made and gave cues to Mosconi. Geat deal for Mosconi, he always had a lot of new cues to sell. Adam does have a deal with the Mosconi estate, much like they have a deal with the Balabushka estate, to make and market cues now. Most of the Helmstetters in this series, are new replicas of the cues Hemstetter made and gave to Willie in the 80s and 90s. Maybe the eBay auction was for one of these modern replicas, maybe that cue was actually one of the cues Helmstetter got into Mosconi's hands, but in any case, none of them were much ever "used" by Willie. I understand Mosconi would take a cue a maker had made and gifted to him and play with it at an exhibition and then, without actually making any claims about his "use" of the cue, outside of what the crowd just saw, offer to sell it. Nice work if you can get it, especially considering Willie paid nothing for the sticks. Just one of the perks for being zillion time over world champion.
Kevin