Yours is the only other example of this type of cantle hinging I have seen, but the chasing seems almost identical to a Kinloch Anderson sporran I have -

DSCF9116a.jpg DSCF9124a.jpg DSCF9167a.jpg

Curiously, the rod-link hinged cantle is on a Forsyth's sporran of a similar construction to yours, and with nut-and-bolt attachment, but the KA sporran cantle is rivited and so not easily removed. Both cantles appear to be silver, but the lack of obvious hallmarks leads me to suspect they are only silver-plated. The KA sporran is also suede-lined.