I'm gonna go "LO" as documented in the vin decoder ... "0" indicates the number of year, whereas "O" indicates the product designation as in "Super Stock".
1st digit: Car make:
B = Barracuda
J = Challenger
L = Dart
R = Belvedere / Satellite
V = Valiant / Duster
W = Coronet/1971-74 Charger
X =...