George,
From what you have described, I'd agree with you that the generator is definately fastened in place. It seems the hard-wired transfer switch is also a permanent installation. But I'd have to believe the receptacle is only going to be used while attended. If it is only hot when the generator is running, it seems that a permanently unattended cord plugged into it would serve no purpose. If I were going to plug something in and leave it unattended for any lenght of time, I'd want it hot all the time. It really seems this receptacle is for unattended use. We are still fumbling around in the '99 code here in VA so it would be legal here.