Missing pieces
 

Putting together a 71 split bumper and have 4 pieces 18 inches long by about 1 inch wide. These are unpainted and never exposed to the weather.car just came from paint shop where windows removed and new hood installed. Can't figure out where they came from. Any ideas would be appreciated.

Four pieces of what? Chrome, rubber, bare metal, or???

Is it an RS (round marker lights next to grill) or an RS wannabe (rectangular lights below bumper)? Sounds like you may be describing the reinforcement and/or cushion pieces related to the RS, which has a center nose extension. If yours was a standard full bumper model that's been RS'd, that would explain the extra pieces with nowhere to go.