OK... That's possibly what the OP meant when he said "I can't get the switch check to recognize the 300." So therefore, without further information on the exact symptom, we might still suppose the dish is not pointed correctly.
Or, he could be looking at the switch with a legacy receiver and a DishPro adapter. My 4900 says "SW64" for my 3-sat setup. I have no idea what it would show if the wing dish were not pointed correctly.
And even if the OP sees "NC" on the Check Switch screen, how is he or she supposed to control the switch in order to point the dish? Can you pick a non-existent satellite on the Point Dish screen?
The cable could be shorting at the DP-34 input. I did this by accident because the F-connector jacks are all covered in a wax-like substance which must be pierced by the center conductor of the cable. It's easy to start the conductor off-center, screw it down tight, and short out the input.
Finally, if this DishPro LNBF came off a SuperDish, won't it be the FSS kind and not work at all with 61.5?