Are my brakes abnormal?

I vote the rears are likely needing a cleaning and adjustment. Brake dust will make the rears not work very well, and I doubt the dealer pulled the drums for their inspectuon. This is easy to so, and if dust is in drum then that will confirm my thoughts. Even though the rears don't do the bulk of braking, not having them work properly puts a bigger load on the front. While you're in there check for any misture or brake fluid leaks especially around the brake cylinder.

Next do a visual on front brakes. Look at your rotors for deep grooves or other abnormal wear. You might also want to pull/inspect the pads to check the surface.

If the brakes are still sluggish, get them bled. Again, if the dealer did not drive the truck during their check up, they might not necessarily find a "fade" in the brakes due to air in lines.

These items are certainly DIYable, but if you aren't comfortable with doing the work, certainly have a mech look at these.