so here are some things that I know about 1970 Darts related to VIN numbers:
LL23 cars were all 2 door Swingers
LM23 cars were all 2 door Swinger 340s
LH23 cars were either 2 door Dart Customs or if they had the A65 option, were badged as Dart GTs
All the L*23 cars were hardtops (no 2 door sedans)
There were LH41 4 door sedans that were badged as Customs
No 4 door hardtops
Now the question: were there any LL41 Darts in 1970? They would be low trim level 4 door sedans, but I don't think I ever saw one. If so what were they badged as, because they weren't Swingers???