Let me start off by saying I'm looking at my old copy of TCR (8th edition-2001) since my new one is at home. So, the information I'm giving you may not be the same as what's in the 10th edition. YOUR CHIP MAY BE LISTED IN THE CURRENT EDITON. With that caveat....

No, there's no listing in TCR #8 as an error chip. There is a listing for a tan color, but not the color you have. I think it's just a new find that will probably be shown the next edition of TCR. This happens pretty often with roulette chips. Variations show up pretty often that haven't been cataloged yet (different colors, table numbers or letters, etc.)

Maybe one of the authors will see your post and comment. Or maybe somebody can check the 10th Edition to see what it shows.