I've been wanting to get into large format for some time, and recently acquired a Saunders 4550XL to get ready for eventual printing. I currently shoot 35mm and MF (6x6), so I was looking into buying some newer enlarger lenses. I purchased a used 50mm f2.8 Componon-S for my 35mm work to replace an older metal Componon. For 6x6 MF and eventually 4x5 LF, I also purchased from the same seller a 135mm f5.6 Componon-S, the most recent version (No.39570), to replace my 75mm f4.5 Rogonar. In my haste, I didn't notice that the lens appeared to be missing the rear element in the images. I just got the lens and realized that there was no rear element. Tried focusing with the lens and it was futile.... 
So, does anyone here have experience with the different versions of the Componon-S 135mm? From (https://www.photocornucopia.com/1061.html), it appears there are three different versions (mine is this one: https://www.photocornucopia.com/archive/86/39569_Componon-S_5-6_135.pdf). Is it possible to buy one of the older versions, remove the rear lens element, and put it on my newer version?

So, does anyone here have experience with the different versions of the Componon-S 135mm? From (https://www.photocornucopia.com/1061.html), it appears there are three different versions (mine is this one: https://www.photocornucopia.com/archive/86/39569_Componon-S_5-6_135.pdf). Is it possible to buy one of the older versions, remove the rear lens element, and put it on my newer version?
