I am curious about the Arnott shocks you chose. They are specific to the Z95 Magneride suspension, not the Z55 Autoride suspension which your Denali has.
I believe the fit is the same, but the Z55 front shocks do not use the Magnetiic fluid which is specific to RPO code Z95.
So while they might fit and not generate a fault code, I would be skeptical that they are actually damping they way the OEM Z55 shocks would.
Did Arnott ever advise you about this or say they are interchangeable?