The fall color you see now is the fall color you will always have.
You are depending on all the right people keeping track of all the correct information going back to the grafter, then the liner sale to the grower had it correct, then the grower to the nursery keeping track correctly, then the loading crew grabbing from the right row in the yard. That's a lot of room for error...
Its not a hydrangea that you can shift from red to blue.
It's true that the red pigment is related to sugar production and a more acidic sap in the leaf as in sumac or red maple tends toward the red, but a Red Sunset or October Glory is genetically identical to the originals and won't show the variability that a straight Acer rubrum will.
Buyer beware
