It appears to be a reamer sticking out of the BACK of the spindle, which means the reamer would be small enough not to have changed the 3mt taper very much at all. The taper isn't going to be changed by a reamer that can pass through the length of the spindle.
My questions is how hard is it stuck in there, and did it do damage to the bearing surface at the smaller bearing location, if it is stuck very hard.
Clausing does have new spindles in stock, I just bought one. Around $245