Hi Carlos,
I love these old folders!
I am able to locate two references to a Sheffield knife maker named Mappin - a
Mappin Brothers and a
Mappin & Webb, the latter of which used the "Trustworthy" trademark, and produced cutlery from 1835 to 1964.
What material was used in the construction of the bolsters? Is it a ferrous metal?
Cheers,
Chris