If there's a large cylinder on top of the boiler, just in front of the stack, it's a feedwater heater. Water from the tender is routed up there and warmed by exhaust steam or hot air from the firebox (not sure how, I'll check).
The cylindrical type was often by Elesco. There was another by Coffin which was bent around the front of the smokebox door. And I think some were inside the smokebox.
You can tell if it burns oil or coal by looking at the compartment at the front of the tender. A coal burner will be open at the top and usually have the representation of a full coal load. An oil burner will have the top closed, possibly with some sort of hatches modelled. Water goes at the back of the tender and under the fuel. You can often tell just where by looking at rivet lines on the side. 6060 has a Vanderbilt tender with a cylindrical water tank; you can easily see the coal/oil vs water containers on them.
I think the 2-10-2 was a big bust for PC. They didn't produce anything the next year. The sets sold for about $100 but are offered at a 50% to 100% markup at train shows.