nope stock drain plug, it'll give it more ground clearance and aerodynamics under the car I guess. Not that you should really need either for a stock car, but GM put the allen bolt in there.
I ordered a new one a couple of years back (have to look up the part number) and got a standard hex head oil pan bolt ... and not the OEM allen head one :-(
The current part number from GM is 3921988, but I belive it's a regular plug since it's the same part number as a 5.7. Now the old numbers attatched to the new number is 14086055 and 3923420 but not sure if they are allen head or not they changed numbers many years ago back in 1990.