Nav Unit Transfer - 2004 Escalade to 2005 TB

My friend gave me his navigation unit out of his 2004 Escalade. I'm putting it in my 2005 Trailblazer. I have already connected it, and it looks like it's going to work I just need to get the TheftLock off of it and have it married to my vehicle. After I do this, should the navigation unit work? Does anyone see a reason why a 2004 Nav unit out of a Escalade wouldn't work in a 2005 Trailblazer? I just want to make sure it should work, before I pay GM to connect the unit to the Tech2 machine and synch it to my vehicle.