i think what you're concerned about is the distributor compatability between the two engines?
If that is the case, then NO you cannot and should not use the 3.8's distributor in the 4.3! This is due to the even vs. odd-fire differences. At the very least the "star wheel" will have to be swapped for an even fire "star."
i think all 3 engines---200,229 and 262 are internal balanced but i will get back to you on that.