Just about all the expedite carriers I know of require dolly legs on your truck to lease on with them. Most of the auto plants will require you use them too. My truck is set up so that when I drop the air in my suspension, the dolly legs are already nearly on the ground, and only a few cranks are required to touch the ground. It is a good idea to drop your air suspension when being loaded and unloaded with forklifts along with using the dollies, although I admit I am guilty of not doing the latter most of the time.
With your spring suspension sterling owner, you will definitely need the dollies. Are you leasing to a carrier or planning on it? many will require the air ride also, so check around before making big plans. Some carriers will accept spring ride, but most of the time it's not the company but the customer who requests the air ride, so the truck might miss out on some loads.
-Weave-