There is a HUGE difference between an internally balanced engine and an externally balanced engine.
That being said, all engines, internally balanced or externally balanced have a HARMONIC balancer. It has absolutely nothing to do with balancing but has everything to with eliminating harmonics...
If I remember correctly the first UDP's used a smaller crankshaft pulley that didn't have a true harmonic balancer in them and the result was crankshaft breakage. The next version used the stock crank pulley and larger P/S, Alternator and water pump pulleys