Archie, are you saying that for the same chip, an overstamped version is valued higher than its non-overstamped (original) version?
I haven't looked at the cochips.com website, but I'd like to see an example of that.

I do agree that very rare chips, like the $1 stamped Gold Star you show, can command significant $$$, because it is not available in its regular state, except for the 4 examples that got out (per Chip Guide notation). Also, some high-denomination overstamps can command a nice value, as it was rare for collectors to take home and keep $500 or $1000+ chips. (Not really applicable in the early days of Colorado chips, as their low betting limits didn't require high-denom chips anyway.)