There's no option in the EPC for the r107 350sl to be a five speed. I think that maybe the w109 and w111 coupe may have had the five speed option, but I'm away from the EPC right now. I think that the 5-speed transmission parts that MBFool needed to do his conversion in the link above are also quite rare.

__________________
Past mb: '73 450sl, '81 280slc stick, '71 250, '72 250c, '70 250c, '79 280sl, '73 450sl, parted: '75 240d stick, '69 280s, '73 450slc, '72 450sl,