Welcome to the forums!
Here's a '73 Overlander right off RJ Dial's website - 73Overlander
The nameplate with VIN is the 2nd pic on the first line -- under the window in front of the door.
The top left corner of this RJ Dial page has two different VIN formats for Overlanders this year - J for Jackson Center or S for Santa Fe Springs. The NNNN is the sequential production number. No, a thousand weren't produced -- there was a range of numbers reserved for each of the models this year and not all numbers necessarily would have been used.
Pictures of your baby?