I just ordered a crown and pinion and bearing kit for my 2005 dodge 3500, because the old ones were wearing irregularly. I was wondering if you need to order a shim kit as well or if these gears dont need to be shimmed

 

All gears need shims. While you're in there I'd buy a master install kit.
Are you doing these yourself?

 

I am planning on getting a mechanic to do it but am trying to line up all the parts in advance. For some reason the dodge dealership told me that i didn't need shims and only needed a differential rebuild kit which includes seals and bearings. but other people are saying that you always shim so I am uncertain

 

The master install kit might include shims, but you'll have to check.
I'd order aftermarket gears, cheaper and usually stronger.