Poor remains of a Jambiya

[Rather]

I kindly ask for your help. A fiend of mine got knowledge of my interest in ethnographic edged weapons and gave me following gift. The remains of, I guess from other posts in the old forum, Arabian Jambiya. The handle seems to be wood, backside covered with silver, the blade is in a poor condition, missing parts of the edges and dark spots of rust. The sheath is missing, only a silver plate with ornaments and stones, I believe it is sard (Karneol in German), survived. First of all, do you think is comes from the Arabian Peninsular? What might be the age? And finally, what to do with it? Leave it as it is or try a restoration? Thank you in advance for your much valued comments.