<font color=blue>But anyway, I'm new and I'll take my lumps.<font color=black>
They (at the store) probably are the same way - new, and will take their lumps. I wouldn't bother with all the work taking it back. Not much to be gained in my way of thinking. I would be more anxious to get it mounted and try plowing with it, after you get it assembled right.
Your first attempt at plowing, even with a plow that is already adjusted, will be frustrating for a newbie, at best. It took all the patience I could muster the first time I had to set up a 2-bottom plow my first time (and that was after I did a lot of plowing with ones already adjusted).
The first pass you make will not have a furrow to drop the right-side wheels into, so the plow won't do very well. The second pass will be more realistic when you have a furrow to drop the right-side wheels into.
The plow may not pull itself into the ground, if the top link is not adjusted to the right length, or it may try to dive too deep if not adjusted. If you don't have draft control on your 3pt, keeping the plow at the right depth may be a source of frustration. Because, if the plow drops too deep, you will lose traction and cause the plow to go deeper as the spinning wheels dig deeper. Raising the 3pt arms will be necessary to gain traction, which causes the wheels to come up, causing the plow to come out of the ground. Depth control keeps track of the load on the plow and raises it when the load gets to the high side, and lowers it when the load is relieved (by raising it). Its an internal automatic control through a mechanical linkage. Your tractor may or may not have it. Usually you can tell if it does if the top link connection at the tractor has a heavy spring connected to it.
I don't mention this to discourage you, but just as an advance warning in case this is a totally new experience. Plowing is great satisfaction when the plow is adjusted right, the ground is the right moisture, and all the debris on top gets buried underneath. Be patient and have fun.
If it gets too confusing, maybe a neighbor (farmer) is available to give you an expert hand.