That is a fine looking rifle! I compared it to my brass mounted rifle and will point out the differences that I see:
1. The cheekpiece "scallop" is different, on my Zollman it does not extend past the comb to the other side of the rifle.
2. Also you can see the cheekpiece has a some what different look. Your rifle has lines or "wings" fore and aft of the cheekpiece, mine does not.
3. In the second picture the rear moulding of the lock panel is slightly squared on my Zollman, yours is pointed.
3. Although the patch box side plates are similar The engraveing is totaly different: Your gun uses wavey lines to border the pieces and lots of "crosshatching"..My Zollman uses lines and "dashes" to border with and there is no "crosshatching". Also the lid engraving is totaly different.
4. Both my brass Zollman and Chris's plainer iron mounted Zollman have the same fore-end incise carving, yours does not.
Having a Zollman rifle in hand I would have to conclude that your gun was not made by Zollman, but to be sure you should immediately send it to me for a closer unprofessional examination!!!...Ed