Because the helmets all came from the same "source," and the prop-makers did a good job of replicating details across multiple helmets, it is easy to make spurious correlations.
So, while I'm sure we would all like a casting of the screen-used ESB helmet, this helmet is not it.
A pair of details that might lead you to suggest it is the ESB hero is the
gouge on the middle of the left cheek edge and the "chip" near the top of the left inner mandible. The Prepro 1, Prepro 3, ESB hero, and ESB stunts all have this gouge. The placement of the gouge is similar on all 3 helmets and the stunts, however the gouges are not exactly the same. The helmets were created to look like one another; they did not have those gouges out of the mold. The above casting is no exception.
Second, I have a picture of the inside of the ESB hero, and the above casting is missing a very noticeable and very absent detail on the RF ear mounting area.
Also regarding the RF ear, the helmet is missing the "ear hump" that is part of the dome and helps support the RF ear. I am hesitant to list that as a reason why this helmet is not the ESB hero, because I suppose it is possible, though I couldn't imagine why, that detail was removed from the mold/casting. Banzai do you have any information on why that is missing?
Third, it's clear from tour photos and conversation with Joe Johnston that the majority of the ESB paintwork is layered through masking and peeling. If the outside of the helmet was cast, the edges of the paint layers would show on the recast helmet because it's, well, a cast of a completed helmet and that's exactly what you would want and expect. Lee's PrePro 2 casting has the layered paint detail found on the PrePro 2, which made me think this helmet should also have attribute. Better quality photos would help determine if those raised paint areas in the right place. But at a glance, I don't see them.
Fourth, that is not the mysterious and over-hyped ESB "warp." It appears that the visor area just got excessively trimmed.
If parts of the helmet were modified, it would appear that the only parts modified were the parts that would positively ID the helmet as the ESB hero, i.e. the gouge shapes are exact to the ESB hero—the likelihood of which is, and call me crazy, very remote.
Instead, the current evidence offers the more rational explanation that this could be some sort of ROTJ ESB-styled stunt helmet, which would share the ESB-style gouges and I could easily see being re-molded. The ROTJ, ESB, and PrePro 3 helmets still have their innards intact, which at least suggests that they were not re-molded.
Obviously, I don't think it diminishes the importance or awesomeness of the casting; it's just not a copy of that particular helmet.
Not sure you can rule out anything just yet...
If you look at the details, it does have allot of Hero ESB gauges..

... Veeery interesting.....I'll be the first to say it.....CAST FROM THE HERO then modified!!!