I think I can recall one for sale in the last 5 years by Kirby (vintage doubles) IIRC.
I believe it was a side bolstered boxlock, such as the ones from Osborne.
Said Osborne is supposed to have provided these guns, or at least the actions to other retailers such as Lancaster and Alex Henry...
Lawn and Alder was more than likely a retailer only.
If you google it, you come on a thread on this very forum.
Best regards,
WC-