It's a VERY nice bucket. Very few were ever made, and the few that are floating around out there are very hard to come by. Unlike the "mystery" helmets, the MSH has no direct lineage to the screen used buckets, it is an original sculpt... but it is still a very covetted piece of many collectors' collections. The reason why I posted this asking for a positive ID is because if it is an actual MSH, I'm obviously going to consider bidding on it.
If Natty says it's MSH, then it's definitely legit. He would know. Thanks guys for giving a positive ID on it. Now I just have to decide how much I can afford to bid, and hope DV1 doesn't outbid me. 