Connie, I am pleased that you had a response to your query and have found out the date for the Blue Tit paperweight. It's a very nice engraving, too.
For a bit of (unnecessary?) extra info ...
With my newfound birdwatcher hat on, and after much searching for information, I agree that the American Chickadee is a member of the Titmouse family, and it does indeed share the same scientific family name. But some American authorities use one Latinised name and others use another. So it's even more confusing than just the English naming that Lustrousstone pointed out.
But, in all the online references I have found, none describe or illustrate the Chickadee in all its forms. They all mention only the Black-Capped Chickadee, which is the commonest. In size and colouring this bird more closely resembles the European Marsh or Willow Tit (which are almost indistiguishable from each other) but the Chickadee has a larger black "bib" on the throat. The Chickadee gets its name from its call ... "Chick-a-dee-dee-dee" (so the info tells me).
The European Blue Tit is a prettier little thing with blue and grey to the back and wings, yellow underparts and white head with black outlining and eye-stripe and a dusty blue cap.
If ever I get over to the US again, I will definitely be on the lookout for the Chickadee, even though it may not be as colourful as our lovely little Blue Tit.