I personally would wait until the grass is rooted and growing well before walking all over it with a wheelbarrow. It looks like you get good sun there, and if you have fertilized and watered as the sod company suggested you might not even notice those spots by the end of the season. But I would be inclined to topdress it too, just give it a couple more weeks to establish.

No expert here, just my $.02, good luck!
Paul