Dunstall "Super" Silencers

Anyone know the background on these? I have a pair I'm debating parting with and wish to know more about them. They're stamp as the others are. Heavier and have no removable baffle plate. Bought used some time ago and was told by the seller that he' run them on a '74 Commando. I don't doubt that as the mounts match up with the Decibel silencers. Thanks.