Wanted 1971 Dodge Challenger R/T panel louvers mounting template


Does anyone have a template and mounting instructions/dimensions they could share for body panel louvers on a 1971 Dodge Challenger R/T. These are the louvers that mount on the body in front of the rear wheels. I'm looking where to correctly mark and drill the four holes for each louver. Stupid question, how can I tell which side of the lover is up? The louvers are not square and are mounted on the car at a slight angle.

Thank you,