The earliest Winchester moulds were made of brass, with no company markings. According to Chamberlain, there should be a very small number (perhaps a serial number) stamped on it somewhere.
That looks like a pristine specimen, wow!
The one on the right certainly looks like another Winchester. The one on the left, I dunno. The handle shapes, hinge and sprue cutter look maybe like the designs some of the smaller gunsmithing shops out West made for their customers, but I don't know whether they made them of brass.
You might ask the guys at the Antique Reloading Tool Collectors' web site about the dual cavity mould.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |