Difference between 73 and 74 Dusters ?
My Demon had a seat belt light on the dash, but not a light for the EGR.
The 73 Dusters had the big rubber blocks on the front bumpers that were not on the 74 & later. (Fed bumper standards raised from 2.5 to 5 mph in 74.)
Vinyl grains on the seat skirts are different on the bench with center armrest.
No Duster 340 in 74 and no Duster 360 in 73.
The other difference not already mentioned is one year.