The sig looks like it is painted with gold enamels, quite normal. Auction houses are the best place to get an opinion on this type as you need a lot of experience to date and authenticate such pieces. Showing to other Daum dealers can be just as good a way of checking. This style of Daum signature is found faked on unmarked cameo, as you only need a relatively low temperature to fuse the enamels this is easily done. So signatures are just a guide. Had the signature been etched on the original blank it would be the same colour as the leaves.
It is sensible to get it checked but do not worry unduly if you bought from a good dealer.