I see this post is fairly old, but I hope you don't mind me "throwing in my 2 cents worth."
Yes, I can say for sure that the '99 Series II, VIN "K" (normally aspirated) is succeptable to the famous failures. At just under 90k miles, my '99 Bonneville series II failed. -BOTH the upper intake (due to bad EGR design) and also the lower intake gaskets failed too, dumping the coolant into the engine oil.
And yes, there is an aftermarket "fix" for the bad EGR design.
By now, you have probably read the other posts related to the intake/coolant failures.