I can’t imagine that they wouldn’t be. On the Dream on the Transatlantic cruise 13 night cruise there were probably two billed as for members and their guests, and maybe 3 for those wanting to learn about DVC. The times were at 12:30 and 4, if I remember correctly.
I don't know if there's a regular day & time. We did a 7 night cruise a few months ago. The DVC staffers initially told us "we think it will be ___ day and __ time", and it ended up being an entirely different day & time. I got the impression that other activities receive higher priority for scheduling the lounge.
Maybe it's more structured on the shorter Wish cruises, though.