My books aren't showing an "812" for 1962. The numbers for 1958 won't help for your '62.
Here's an exerpt from our FAQ page on what to look for on an SS:
1962-Supersport option RPO 240 cost $156.05 and included; bucket seats, front seat console with flip top lid with drink holders for the rear passengers, front passenger assist bar, special wheel covers, side molding inserts, Supersport emblems and a special plate on the console when 4 speed was ordered.
Unlike 1961, any engine could be had in the Supersports of '62, The base engine was either the 170hp 283 or the 135hp Hi thrift six cylinder. From there you could move up to optional engine RPO 300 which was the 250hp 327 for $137.75 (used a WCFB), RPO 397 300hp 327 (used a carter 4bbl), the RPO 580 380hp 409 for $320.65 or RPO 587 409hp 409 for $321.21 (2.20 inch intake valves and larger ports)
All 4 speed 327's and both 409's came with a tachometer mandatory. You could however order the tach seperately for any car for $48.45 (RPO 331)
Check the interior trim codes to help confirm an SS car as the Supersports had their own unique codes due to the buckets and all vinyl interior. (see the interior trim code charts on this site)