First off, you should go take the second clerk (the one who talked you out of the 770) a good cup of coffee... you avoided buying one of Remington's worst products ever because of his advice!
I have a rifle very similar to yours, except mine is stainless (and now sits in a McMillan stock and wears a Minox scope). I don't know who serious you are about shooting, but I might think about putting away some pennies for a scope replacement... I had one of those Remington 3-9x (be-branded Bushnell) scopes, and I dang near ripped it off at the range, just so I could shoot it with another rifle.
The magazine... you have what is called a blind magazine or ADL, meaning you can't see the bottom of the magazine. The other configurations are BDL, with the floorplate that you can open to dump the magazine contents, and a DBM... detachable box magazine.
BTW, Remington rifles that come from the factory with a DBM have the feed rails in the magazine, and can't be converted to an ADL or BDL.
I know, that was probably more information than you wanted or needed.