I’m planning on building either a M4 or a M36 from the Pakistani army
I’ve seen images of their tanks using duckbill tracks.
From most of the aftermarket tracks I’ve seen, they show the duckbills ONLY being added to the outside of the track but I have images showing them on the insides in the images below
As far as I can remember you can add Broncos Duckbill addition to one of their track sets of your choice easily on both sides:
You would just need to check the number of duckbills included in the set and may have to purchase two duckbill sets for that task. As mentioned: They fit nicely on one of Broncos track sets as they are made for them…
Duckbills would not fit on the inside edges of the track on standard M4’s. The E9 suspension upgrade provided spacers that moved the bogie trucks away from the hull, allowing duckbills to be fitted on the inside of the track as well. These upgrade kits were developed during the war, but only appear postwar, usually on rebuilt vehicles being exported as foreign aid.