New CNC Mill on the horizon

[fvfdrums]

Quick question that I was trying to get answered earlier in the year but never got a definative so I thought I would get "paint" involved.

I was wondering if the BK12 bearing units have a rubber seal in them before the 2 bearings in the houseing and if so does the machined end of the ballscrew stop at this seal or the black part at the back of the unit or doe it fit right up to the bearings inside the unit. Picture attached is it A or B or even C and I am way off!

On a separate note I am awaiting the arrival of some profile rail and bearing carraiges, managed to find a good deal in the end and they are now in the country according to Royal Mail and out for delivery so there is a chance they may turn up today which would be great.