Unfortunately, in my humble opinion (though I'm 99.97% certain that I'm correct), it's a modern reproduction, made within the last two to three years--long after the DI was closed. Atlantic Standard Molding company sells blank chips in classic molds (such as this Horse Head Right mold, but also HCE and other molds) through its website, www.pokerchipsonline.com for something around $0.50 each, depending on quantity. Just over three years back a bunch of classic hot stamps came up on eBay (including this DI stamp, but also Dunes, Silver Slipper, Sands, etc.). A chip collector picked them up, and will stamp these dies on your chips for about $0.25 a side. Here are details:

http://www.chiptalk.net/forum/poker-chip-gallery/44532-t-mold-hot-stamps-asm-hh-mold-how-did-i-do-dunes-sweet-5.html

Post 45 in the thread has a link to a slide show showing Dunes, Silver Slipper, Hacienda, Sands, Landmark, Mint, and DI, plus he picked up a bunch of denominations as well. Later posts in the thread show stamps on other molds (such as Lg Key) as well.

The unfortunate thing is that someone may have had this set done just for their own use, and was not intentionally trying to pass them off as authentic (I considered getting some non-denom HCE chips hot stamped with this logo, just because I'm a huge DI fan), but the risk is very high that someone gets a hold of them later and tries to pass them off as real (or at least they get passed around, the provenance gets forgotten or is obscured, so people down the line start thinking they're real). Of course, I have no conclusive evidence that this chip was among those recently hot stamped (ergo my 0.03% margin of uncertainty), but everything in my view points to it: a bunch of new chips showing up at once (I've seen a dozen or more on eBay in the last year); HHR chip (not sure when ASM got out of the Vegas market, but it's been years) with a early- to mid-90's DI Logo; etc. It's a neat looking chip, but in my view not authentic.

As to how much it's worth, I've seen them go for as high as $30 (from a well-known dealer in rare chips, even after he disclosed my doubts about their authenticity in the auction), but for a long time there was a seller on eBay (actually at the same time as the $30 auction) who had them BIN for $3. For a single chip you might want to pay that much just to have one; however if you want them in quantity you could buy the blanks from ASM and have them hot stamped yourself for about $1 each.

I hope this helps

Brent J. Jensen
R-8007
orbis non sufficit