A 209 primer fits into a hole roughly 1/4" diameter at the rear of the breech plug. A #11 cap with fit on an appendage or nipple at the back of the plug. Open the Wolf and look at the breech plug. Then do the same with the Staghorn to see if its the same or if there's a nipple instead of the primer pocket.

I just checked and the Staghorn uses the #11 caps. This gun should be used with blackpowder or Pyrodex, maybe triple 7 granulated powder, not the BH209 powder. The action design is wrong for the BH209. Your Wolf will handle the BH209 nicely if you buy the conversion plug from CVA or Western Powder and this is the powder I'd recommend you shoot.