In theory, yes! That's what signet rings are for after all. Not sure how well it'd work with how it was engraved, might get wax stuck in there for ages!
Hey guys. I would have posted this sooner but I've been rather ill :( Anyway, I opened a present from my mother on Christmas morning, only to have this little guy grinning at me! She had it custom engraved in a solid silver signet ring! Beaut isn't it? Thought you guys might enjoy seeing it.