Andrewk. Really? the rotor swaps over too?!!!
Well #$%*. That wors for me man. I've asked around regarding late F's and got a bunch of this and that.
How the spacing?
You were probably getting fed information about the front brakes, which are different. I see a lot of confusion about it.
The late F comstar rear wheel uses the exact same rotor as the early F spoked wheel. Same part number.
The difference between the early and late rear brakes is that the early one was a non-floating design, and used two pistons. The late model uses a floating design (so caliper can be removed from bracket) and a single piston, but the caliper bracket is the same dimension at the wheel axle spacer portion as the early caliper, so spacing is on.
Only change you might have to make is the rear brake line, which I'm sure is on your radar if you're thinking about flipping one.