The 1969 Chevrolet Camaro is a poster child for the golden age of muscle cars, but an example heading to auction with Mecum at the company's Dallas auction this month is no ordinary Camaro.

According to the auction listing, this car is one of an estimated 58 COPO Camaros built with the RS Package. COPO is an acronym for Central Office Production Order, a backdoor method enterprising dealers used to special order cars with high-performance engines. In this case, the dealer was Berger Chevrolet of Grand Rapids, Michigan.

Thanks to the COPO process, Berger was able to have this Camaro built with the L72 V-8, which displaces 427 cubic inches and is rated at 425 hp. That power is sent to the rear wheels through a Turbo 400 automatic transmission and 12-bolt Positraction rear end with 4.10 gearing. Other non-standard features include power front disc brakes and a ZL2 cowl induction hood.

Any COPO Camaro is rare, but this car is even rarer because it's also equipped with the RS Package, an appearance package recognizable by its hideaway headlights and unique grille with a centered "RS" badge replacing the Chevy Bowtie. The RS Package was a popular option in 1969, but as noted above, it was unusual for a COPO Camaro to get it.

1969 Chevrolet Camaro Berger COPO RS (photo via Mecum Auctions)

1969 Chevrolet Camaro Berger COPO RS (photo via Mecum Auctions)

Mecum didn't publish a pre-auction estimate for this car, but early COPO Camaros are among the most valuable classic muscle cars. Factor in this car's added rarity, and it's likely to sell for big money when it crosses the auction block.

The original COPO Camaro died with most other classic muscle cars as the auto industry shifted focus from performance to meeting newly mandated emissions and safety standards. Chevy brought the COPO name back, initially on a concept car unveiled at the 2011 SEMA show, for a turnkey drag racer, and has continued to build limited numbers of these cars. It even built a one-off electric version, dubbed eCOPO Camaro, capable of a 9.51-second quarter mile.

The auction is scheduled for Sept. 22.