its possible for buggies to wheelie, but they have to do it in a slightly different way than monster trucks.... for all intents and purposes relating to wheelies, a buggy doesnt have any height but a monster truck does, and what matters is the location of your center of gravity in relation to the rear wheels.... for monster trucks, the center of gravity is considerably higher than the level of the wheels, and so when you accelerate forwards, you do not push directly at the center of gravity , instead you tend to 'pry' the whole truck upwards....
for buggies, the center of gravity is in line with the level of the wheels (or they should anwyay, otherwise thats one unstable buggy) , and so it should accelerate quicker than monster trucks and still not wheelie.... to wheelie, it takes the pivoting action of the rear wheels to lift the whole buggy off the ground, as if you have held the rear wheels still and the torque is lifting the weight of the entire buggy up... it takes alot of traction and torque to wheelie with a buggy, i'd say its an uncommon sight to see one do it...