might take a while, but you could search through the car **** posts to see if there is a high res pic of one with an open hood, then cross reference with what you have to work with.
I have a latch panel from a 72 duster in the garage if you want me to send over a few pics pm me. Not sure if it's close enough but thought I'd throw that out there
just looking at
this ( demon engine bay ),
this ( 72 Dsuter engine bay ), and
this ( 73 Duster engine bay ), you may have a lot of work ahead of you.
For those that don't want to hit the links,
The Demon has a VERY flat latch panel with one hole and the spring and does not connect to the radiator core support at the center
The 72 Duster has a similar panel with a depression in the center where the latch goes through and connects at the core support
The 73 Duster has a small rectangular latch panel that connects the grill to the core support at the center only...
I'd say that it would be possible to modify the 73 latch panel as long as you take into consideration a couple of things:
1. latch depth in relation to hood and core support
2. latch panel reach in relation to distance from the grill mounting holes to the core support ( depth may play a part as well )
3. Will there be enough grill support with a center only mount