There is a tag on the drivers side door, the VIN number is on the tag. The fifth digit should be a J if the truck is amn LRT. The fendertag is on the radiator support. As for the build sheet locations, maybe under the carpet, above the heater, or under the seat.

70 Charger R/T SE 472 Hemi 70 Charger R/T convertible 70 Charger R/T V Code Sixpack 69 Charger R/T SE Sunroofcar 68 Charger 383 68 Charger 318 71 Charger R/T 70 Challenger convertible 71 Challenger convertible 71 Cuda 340 09 Challenger R/T Classic