C3 threaded holes

[ab56452001]

Hi all , ive looked all over the place for answers but come up blank ! . On my Sieg C3 the cross slide front lower lip has 2 x 6mm ( I think )threaded holes about 2 inches apart , im guessing these are to mount a Follower Rest ? . Also on the , i think its called , Compound Rest to one side of the Adjuster Dial are 2 smaller threaded holes , anyone able to give me an idea what these are for ? , cheers.