Rotor MAS spider

petr.bauch

I bought a second hand Rotor 3d+ MAS but failed to install it. The frame has BB386 shell and I have Rotor PF4630 bottom bracket. It seems that the crank arm does not reach all the way to the drive side. I wonder if the round part in the center should be there: it protrudes towards the frame effectively like a spacer. Does anybody know if it can/should be removed and if so, then how? Photo