[Slater]

Do all shotgun barrels have a similar thickness to the barrel walls? Excepting, of course, the Mossberg 590A1 with it's heavy barrel.

[Dave McCracken]

Not really, there's a fair amount of leeway. Usually, the lightest barrels are those that are thinnest and best made. And of the finest steel.

Apples to apples, the Remington Light Contour barrels run 4-5 oz lighter than their standard counterparts, and oft more. That doesn't sound like much until one actually shoots the things, the LC barrels seem much quicker while retaining the inertia of the heavier ones. That is subjective, so YMMV.