Nice piece. I bet you were happy to pick that one up. I knew that there were 40 of these made. I wasn't aware of the additional 20 that were destroyed. I also have a Phrobis Int'l with black fittings and a bright blade.
Several years ago I came across another of these all black Phrobis Int'l M9 bayonets. It was mounted on a dark colored wood plaque with a USMC emblem. The plaque is completely different from the Phrobis chevron plaques but the component parts are identical to those used on them. The M16 barrel and mounting block are the same as the chevron plaque, as is the engraving on the brass plate. I suspect that this was made by Phrobis or someone with a connection to the company. I sent pictures of this plaque to Mickey Finn shortly after buying it but he never commented on it.
Keep your eyes open guys, there should be 36 more of these bayonets floating around out there.