Of course you can.
These 4 weapons "model-modifiers" are pre-defined effects.
-1 -> no change to weapon appearance
0 -> "blue" for (usually) water effect, adds Effect/item_L.eft to the weapon
1 -> "red" for (usually) fire effect, adds Effect/item_F.eft to the weapon
2 -> "green" for (usually) earth effect, adds Effect/item_E.eft to the weapon
3 -> "white" for (usually) wind effect, adds Effect/item_W.eft to the weapon
these effect files contain a reference to the neutral smog shape (Effect/DDS/smo07.dds for several) as well as color and coords of floating points.
you can change the shape with a (multi)colored one to change the blow effect.
this means that blow-effect is added to the weapon model - and thus does not depend on the basis one used to draw the actual weapon shape, blow can so be added to any weapon.