Did you know that THCA, the natural form of THC as it's found in the fresh plant, is a polar compound? Being a carboxylic acid it would have to be. To make it more soluble in nonpolar solvents, like butane, you would have to "protonate" it with a protic acid, like HCL. But for that to happen it would have to already be in solution, so it's sort of a catch 22 situation. So it may be better to use a solvent with some polarity, like an alcohol or ester like ethyl acetate. However, if you decarbed the material before extraction it would then be less polar.
Since there's no real drawback to decarbed extracts, aside from possibly faster degradation, it might be worth doing. But you wouldn't get shatter from THC, because it doesn't glass up like that, stays gooey. But does that really matter, aside from making it easier to handle? It may actually be more potent too, because decarbing by smoking is probably more wasteful than slow decarbing with an oven or whatever. I doubt if it all decarbs in that instant. Maybe but maybe not, I don't know. Anybody ever try a decarbed extract? If so, did you notice a difference?