Chain-case variance's.

I recently purchased a 1962 / 63 series 3 chain case on e-bay and sent it off for chroming. No problem, except on having a better look the chain case had the cut out / recess for the kick start arm but only one strengthening lugs / bar underneath the kick start spindle. My original chain case (June 1963 series 3) has the cut out and the extra 4 off ribs / lugs molded in the casting around the kick start shaft. I first considered that the one I purchased was a series 2 but was informed that they do not have the cut out / recess. Now there is another chain case for sale on e-bay exactly the same as the one I purchased (cut out but only one lug / bar). I contacted the seller who informed me he removed it from his 1962 series 3 Li150. So I am now thinking that for the early series 3 models they had only the one lug / bar strengthener under the kick start shaft and was modified some time in 1963. I have looked for an Innocenti mod / update but cannot find one. Can anybody confirm?