Appears to be Golden Oak. I think it's the original finish. The insides of the drawers are not finished and look very dark. The backs of a few of the drawers look like they've sustained some damage (cracked or look like it's been gnawed away) but they are completely functional. S-Roll. Drawers to floor on the left, one drawer and a cabinet with cubby's on the right. There is also a door with an open space on the right side of the desk. There are pull-out writing surfaces on either side. There is a working (though difficult to open) lock on the roll top. I have the key. Dovetail and Mortise and tenon construction both evident. Desk comes apart into three pieces. There are rolling casters on the either side (One one side, the wheel is broken off, but it's not affecting the way the desk sits on carpet.). The back and sides are paneled. There is no kick panel in the center.
Re: Roll top desk
Roll tops were made from the late 19th century through the 1930's. Hundreds of thousands of them were made, as virtually every office at one point was full of them. Values depend entirely on condition, size and how ornate they are. If yours is in good condition, at $1500.00 you paid about the going retail for a comparable desk.