different versions of wegner's sawbuck ch 29  

hi,
does anyone know if there where different versions of the ch 29 by hans wegner, i have two sets of four chairs, both sets are the uphoulstered version, one is marked so i am pretty shure these are original ones, the other set though have exactly the same dimensions only the front legs are about 5mm thicker and they are not marked, judging by the state of the chairs i would say they where produced somewhere in the sixties... this seems a bit old to be a fake... any ideas??
thank you