Hi,
I just received my K1 visa (yay!! That was really fast since I had my interview on monday!). The Montreal Consulate also returned my original Birth Certificate document but they didn't return other the originals of my Police Certificate and my girlfriend's employer letter.
Am I going to need those documents when applying for AOS?
Thank you!

congrats... I'm just curious, but did you start tracking the envelope through canada post? if so, how long did it take before it was in their tracking system? I'm unable to track anything right now.

You will not need a police certificate. You will need an updated employer letter when you apply for AOS (unless you plan on getting married ASAP after entering AOS and nothing has changed at her job (ie. no raises, no changes in job description, etc).

Right, those original documents are theirs to keep. They returned your original birth certificate which is yours to keep. If your police certificate had any items noted on it - ie. you have a record - then you will need to provide a copy of that with your AOS and later your Removal of Conditions and Citizenship, along with any related court documents. If you had no record or court documents then you do not need to provide your police records again.

You will need updated employment information for the AOS Affidavit of Support even if the information is the same. Just have your employer redo the same letter if the information is unchanged and change the date. Read over the AOS requirements first, though.