I've been eyeing up the z3100 for months now and this has pushed me over the edge - finally replacing my 4800 so I can print a bit larger and not have to pay the Epson tax to switch from matte to photo black....
Look up the posts in this forum on the starwheels and pinch rollers. Those posts include photos of those new parts. Compare the photos to the parts in your printer and be certain that your new printer includes those parts. (The new starwheels include black plastic pieces at the ends to raise and lower them, and the replacement pinch rollers are tan and not black.)
Yes, there are those who will respond and say that the new parts are not necessary and their own printers with the original parts work just fine. But there are just as many who have reported problems with some papers using the original parts, and subsequently reported that the new parts solved their problems.
You have spent thousands of dollars on a new printer, so it is crazy to get it without the up to date parts.
My recommendation, posted in other threads, is that this be a condition of the sale -- that the printer have the new parts when delivered. That puts the onus on the retailer to get the parts replaced at their shop, thus saving you from the hassle.
Since it may be too late for that, but presumably you are still within a 30 day return window, you need to insist that the retailer arrange for the part replacement if that is necessary. Let the retailer deal with the hassle of arranging for the part replacement with HP.
I don't know what HP service and tech support is like in Canada. In the US some have arranged for the part replacement with no problems. Others have been really jerked around, and told they have to supply test prints proving they have a problem despite the fact that HP knows the original parts are defective, for why else did they make replacement parts?
HP began replacing those parts on the original Z3100 series many months ago. Your new printer should include the new parts. If it does not, then insisting that the retailer arrange for the replacement of the parts is entirely reasonable.