Dalko - The option description on my truck say "Heavy Duty Snow Plow Prep Group" which, as I understand it, gets you the 'heavier capacity' front coils even with the Off Road Package. Sorry, I don't know the dealer order code.
I've looked at that package on the Ram build site, but it doesn't specifically say that heavier springs are included.
By the way, I'm real glad to see more members on here buying and building up these Ram 2500/3500 platforms (both the diesel and gasoline). It seems Ram has made a lot of improvements to the most recent generation. Hopefully, with this growing interest, the aftermarket support continues to grow (AEV's market support is already a good step in the right direction). The Power Wagon still seems to be in a class of its own; fuel economy may not be anything special, but the offroad prowess of that thing is unmatched by almost everything except a Jeep. Looking forward to more updates on this and similar build threads!