It could be done with this one, but would need a lot of work. The biggest issue is the step up at the front and smaller front oval.
I did similar with this exact trailer to make the larger M1062 Bult Fuel Trailer.
Maybe, but they are the older M131 Vietnam-era fuel trailer and have a totally differently shaped tank.
Maybe. If they do, I hope they update the molds or go w/a 3D print instead. I have one and it is really rough and will take a lot to get it all cleaned up and looking right.