Help With CO Centennial/Us Bi-Centennial Medal?

Welcome!

I've seen these in silver and bronze. I don't think they are "rare".

The Colorado Centennial / US Bicentennial medals were struck in three metals, bronze, silver and gold; a portion of the bronze medals were gold-plated. All of the medals were struck at the Denver Mint.

The medal in your image is one of the bronze examples - they were available in the red / maroon slide cases yours is in. The gold-plated bronze medals were sold in black cases, the silver ones in blue cases.

Mintage of the silver medal totaled 20,200 and the bronze totaled 46,000; 5,000 of the bronze medals were subsequently gold plated. The 0.900 fine gold medal had a mintage of just 100. You reference seeing a selling price of $2,000 for one of these medals. I have to believe it was a gold example because all of the other medals are relatively common and do not demand such a high price.

I have seen and/or purchased multiple examples of the medal you've shown at coin shows I've attended - all were priced under $10 (with and w/o the case); I've seen the gold-plated bronze sell in the same range or just slightly higher. Some dealers recognize that the gold-plated medals are less common than the "plain" bronze and therefore try to sell the medals for a bit more - $15/$20 range. The silver medals often are priced at $35 and up. Prices for "Sold" listings on ebay are generally in this range (but can sometimes be a little higher) - asking prices on ebay are often higher but shouldn't be used as a guide to their market value (only "Sold" listings should be used).

The three medals were also available in a limited run of numbered sets (bronze, silver and gold-plated bronze); I've included images of mine below.

An interesting collecting side note, the medal's reverse was later paired with an obverse die depicting the Denver Mint building. These medals were sold individually and as part of some Denver Mint souvenir sets.