The >'70 hoods will have a provision stamped into the hood where a bracket attached. This bracket is used to to secure the safety latch pull rod release.

The 1970 Challenger Rallye hood do not have this stamped into the hood.

The leading hood area where the trim attaches may be slightly different too. However, the stamping/bracing for the bracket attachment or lack of, is the easiest way to determine 1970 hood IM0.