BUT, just in case they don't, I found a few places online that carry stands, so here they are:
CHROME STANDS: Goes with most every color theme. It's safe to go with this stand, since my table numbers are usually pretty decorative, you don't want anything to take away from the number signs, nor the centerpiece. So i always suggest that brides make sure their venues have this on hand. I found this at Kerekes at a decent price, and it looks like you don't have to buy a minimum order like other sites do. Depending on the height of your centerpieces, you can choose different heights of stands.
VINTAGE: Or if you want to use photos or SIMPLE number cards (which I can create for you to print at home at 4X6 sizes), I saw these stands online. A bride I'm working with actually had it on her wedding site, so I searched, and found the site that sells them at Shelly B Home and Holiday. They can also be used to display menus, guestbook, or other items at the receptions. Very vintage chic.
But, one can always go with the frame easels that are sold at Michaels, or if you have patience to search online, ebay sellers may have something fancier. Here's a photo of a table number using a simple black wooden frame easel I got from Michaels.