the answer to your question as I see it is iether yes or no, depending on what you mean. If you mean that it was formed from one giant collision then I think its possible but unlikely since as deoxy99 said we aren't an elliptical galaxy, but all galaxies are believed to be built from a small core galaxy at the beginning that eats and joins with others to form the modern galaxy, in fact the milky way is currently eating several dwarf galaxies.