Hi guys,
I began researching this helmet a few months ago. While I have not seen it in person, I have seen a number of photos different/better than those posted here.
Everything I have seen on the piece is consistent with other Jedi helmets I have seen in person, aside from the obvious missing paint and decals.
I have been researching the possibility that such a helmet could have been used as a deep background piece on the docking bay in Jedi. I have found evidence of one helmet without the rear decals, but no evidence thus far of one without the frown/front decals.
Also, I believe a theory was put forth at one point that all the Jedi helmets used in the UK had foam linings and those used in the US had the hard hat linings. I have also now seen evidence of the hard hat linings being used in the UK. I can't explain the differences between the two linings used in the film. Perhaps they simply ran out of hard hat liners at some point.
Regards,
Brandon