Congratulations on your landing interview Inladappl!!!
Let me just point out that there is a difference in documents needed for inland and outland applications. Since you applied inland, you cannot get a permanent SIN until after your receive your PR card. There are a few landing offices (local CIC office) who will have Service Canada representatives available at your landing day to help you out with SIN but not all. If that is the case you are out of luck, you have to wait for your PR card. For outland applicants they can just show their COPR and visa stamp foil attached to their passport, I know it sucks for inland applicants.
Have you applied for an Open Work Permit? If you received your OWP, you can get a temporary SIN in the meantime so you can work then just apply for a permanent one later on. If you decide to get the temporary SIN please do this before your landing interview because your local CIC office will ask you to surrender your OWP on your landing date.
Review your landing letter, they normally inform you in that letter if a service canada rep will be available to help you with SIN on the same date.