Last 1972 dodge demon built?

This can get complicated.

Until the end of the 1970 model year, the typical model year ran from August 1st to July 31.

For the 1972 model year they started earlier, approximately the 2nd week of July & went over & beyond a typical model year rage at least a week into the 'second' August.

So 14 months involved instead of the former 12.

The cars were not built in VIN order, so going by the highest possible VIN is out.

Starting towards the end of the 1972 a new Mylar door sticker was put into use that has a MDH code for Month Day Hour.

That date often does not agree with the date on fender tags & other documentation, that date is the SPD (scheduled production date)
The SPD is the date they HOPED to build the car when the order was first entered into the system.

So if your car has the new sticker with the MDH code, you would need to compare it to the stickers on all the other cars made like yours to see which one had the latest MDH.

Since no database for that exists & since many of the cars no longer exist, the original question is just impossible to answer.