Checking over Dale Seymour's "Antique Gambling Chips", it appears that ivory chips were made from prior to 1783 up to 1909 or thereabouts with peak ivory production in the 1850s to the 1870s.

I don't think anyone has a date on the horses. An educated guess would be late 1800s.

At this momemt I don't have any traders. I may have one in a couple of weeks. However, ivory collectors, in general, a pretty intense lot and horse heads are quite popular. We'll see.

Both sides are identical. Actually I shouldn't say identical since every chip is hand carved. If you'll note, no two chips are identical. Imagine getting an order for 500 chips. That's 1000 horse heads that have to be carved and look reasonably alike. Quite a feat if you ask me.