I assume the latter is the case, right? If so, there's no need to work exclusively with the addTemplate/removeTemplate trick. You can simply add whole objects to your map

How? Easy: Just take the objects.con of the vehicle you want to modify, and put it in your extracted map folder: MAP\objects\objectname [Actually it doesn't matter WHERE in the map you put it, but having things cleaned up is always good].
You only need to copy the parts of the object that you actually modify, so if no changes to the geometries.con or network.con are made, leave them be.
After that, modify your map's init.con and add the following at the very bottom:
run objects\objectname\objects.con [This tells the game that on loading the map, it also should load this specific file, applying any changes it finds in there to the vehicles on this map and this map only]
That's all. And this allows you to make all the changes you want to the objects.con .
You even can have mapside different geometry (standardmesh) and textures for vehicles, just put them in map\standardmesh and map\texture (NOT textures! There only are terrain textures here!), no need for any "run" commands for that.
You also can just check out Battle of Britain or Philippines, they are DICE maps that have mapside moddings (Ju88, radar tower, PT Boat).