I have never needed to, but dealers can upload the factory tune on to the ecu, overwriting what is in there.
I've run mine with the stock tune for short periods of time (a week or ~40 miles) with an O/R X-pipe and it didnt throw any codes for me, but doesn't mean it won't for someone else. I'd ask them ahead of time, but if you order a tuner from BAMA or any of the others out there, I assume that when you are loading the tune, it will treat whatever tune is in the ecu as the stock tune for "returning to stock". I am sure you are not the first one to have an unknown tune possibly loaded on your car so they can answer that probably quickly. If it is running great right now and no issues, I wouldn't even bother touching the tune until you need to.
The stock springs are black, struts are black, and will have a part number on one of the coils of each spring and will usually have FoMoCo on them. I have stock ones sitting around if you want a comparison. Or you could have the dealer check it out for you whenever they have it.
2011 GT Sterling Gray Metallic - Roush Supercharger 85mm Pulley, JLT Big Air Intake, VMP Tune, Stainless Work 1-7/8" Long Tube Headers, O/R X-Pipe, Retro Muffler, Tokico D-Spec, Steeda Ultralite springs, BMR LCA&ReLoBrackets, J&M PHB, Tremec Magnum XL, McLeod RXT, Aluminum Driveshaft, 4.10, Eaton TrueTrac, Moser Axles
1993 LX Vert Electric Red (Under Construction) - 306, GT40 Heads, Tublar intake, E303 cam, Forged pistons, 70mm TB