Prunus blossom ginger jars

I've had these a while and can't even remember where they came from! The one with the lid has a cork which creaks and groans when I try to remove it so I've left it alone.

Is there any way to figure out how old they are? There seem to be a lot of them around and I've seen reference to double circles on the base, and both of them have these. They're not painted with the cracked ice effect of the very old ones but I'm curious.