If there were 3 known of a chip for the most part the second and third would usually go for less, if condition was all the same. For something super rare like a strip Vegas Sands all could potentially sell for the same. If in an auction though usually the first would go the highest but there are always circumstances that can change that.
In this case there could be say 10 of these and the demand is not there for all known to bring a strong price. Reno dimes are not the hot ticket.
I was just looking for information on this. I saw a few at a show a couple years ago. I know a few were already around and I was trying to learn more about this chip. I kept it as a rarity 9 and your price is very fair.