In my experience the dances at Barn Dances are a mix of new and old. Some even date back before 1646? (pedants feel free) when Sir Roger de Coverley was published in Playford's Dancing Master, though the Sir Roger referred to was The grandparental Sir Roger, so it is older than that, at least. As for "Country Dances" I am less familiar with DEFASS dances but the Squares and Contra variety seem to be more heavily populated with modernity.

Now with E-ceilidh (cue Scots/Irish ire), there are a surprising number of trad dances that come from all ages - like the Dashing White Sargeant (pick yer spelling) Who seems to have been born in the 1840's with a known Scottish choreographer. But there are fashions like Cajun and French (and Breton) that seem to have their moment. And fade slightly, but not in the Red camp.

I think the answer is yes, no and can we re-phrase that question?