As a conferral driver, am i insured to appropriate stock down the stairs of my customers premises?
Answers: Insured for what? Workers comp? Damage to the load? General liability?
No one here can answer that cross-question - you have to any ask your employer, or ask the agent that writes the policies for your employer.
I can tell you one article, though - for workers comp, the rate for a driver is much, much lower than the rate for someone who loads and unloads. If you do ANY loading and unloading, the FULL CHARGE for you on workers comp has to step to unloading and loading - which will cost much, much more for your employer. And coverage for loading and unloading can be a bit odd, between the commercial auto and the common liability.