I volunteer a day a week at my church and have repaired and modified old church pews. My experience may or may not be applicable to the ones in the above. The pews I have worked on have screws from the bottom side toe screwing the back and bottom into the ends. There was a piece of trim covering the screws. It was a simple matter on these to take the ends off. Then the back can be screwed off the bottom. In the end you have a back, a bottom, and ends. Those are much easier to haul away. I also have used the wood from pews that my church was throwing away. It is mahogany, not oak in my case. The shape of the pieces prevents getting 3/4 inch thick boards from part of each piece. 5/8ths is about all I can get from the thinnest parts. You can cut it into pieces and get a lot of it into a thicker board with about a 5-6 inch wide thinner piece. The ends of the pews I've worked on were mostly MDF with hardwood on the top and bottom. The upholstered pews have all had plywood under the upholstrey.
Please do not take any of this as trying to disagree with Eric. He knows more about these specific pews. But I would show up with a pry bar, a hammer, and a screw gun if I was interested. It is likely you can disassemble them quickly to much more manageable pieces.