1. Why don't you look at the rim to determine the manufacturer, not the spec sheet. If there are no markings, it's different than any I've ever seen.
2. Is this some kind of cruel joke; of course the rear wheel has different length spokes (usually about 2mm or so shorter on the cassette/freewheel side) in order to accommodate the necessary dish, but isn't your wheel already built. You just need the dish corrected in order to have the wheel in the center of the frame. The spokes don't change the rim and have no influence on which tire(s) fit. This is a function of the rim width.