It's a 1980 only VIN. They don't appear to differentiate on coupe or targa.
https://www.stuttcars.com/technical/vin-decoder/
MY1980 911 SC
12––5
91 – – 1 - 911
92 – – 4 - 924
92 – – 8 - 928
3
Model Year: A - 1980
4
0 (zero)
6
0 - 928 170/177 kW
1 - 924 92 kW, 928 170 kW
2 - 928 S
3 - 911 SC, 924 85 kW
4 - 911SC, 924 Turbo 125 kW
5 - 924 Turbo 110 kW
7 - 911 Turbo
78910
Serial number