Shamshir origin and age help.

[10thRoyal]

Thank y'all very much for your input. Is there any hallmarks that help with determining age of a shamshir? I know the basics of identifying place of origin but to me there doesn't seem to be much change in form over the past couple centuries.

The edge of the scales doesn't seem to match up quite well enough with the tang for me to think the grip was original.

Also, any rules on applying mink oil or conditioner to the scabbard to keep it from cracking or drying out further?