If it was made by any of the companies who made the Shopsmith's over the years it will look like the ones in the two pictures below. The first picture is the older ones and can use the "old" style knives. The one in the second picture is the current Molder Head.
There are Molder Heads from other manufacturers that can fit on the Shopsmith but use their own knives for them. If the one you bought does not match any of the ones pictured than you will need knives from it's manufacturer.
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ metal ends & retractable casters.