Figuring out a possible date code range for my car.

If you have the OE engine and diff gears the date should be stamped on them front of block right side (assuming V8) under head. On ring gear stamped into the edge if the ring gear. If memory serves me the engine and gears would be between 1-3 months in advance. Other parts like alternator 3-6.

MMC Detroit
Extreme Mopars.com
The 1970 Hamtramck Registry "Date Codes 101" (Page 1)

Good luck