Leica manufactured the Type 2 Summicron in two versions - the regular one as well as closed focus version (or dual range), which had an identical optical formula.
However, my impression is, that the later rigid Summicron (post ~1960) have better coatings. They have slightly improved contrast especially wide open.
All pictures taken with Leica M3 and MP with Leica Summicron 2/50 rigid. Black and White film developed in Xtol. Scanned by meinfilmlab on Fuji Frontier.
I had my version, 1965, CLA´d in Wetzlar. After the lens returned, it produced razor sharp images with high resolution. At 5.6 it been almost to sharp on film, but beautiful on Leica M9s CCD Sensor. You find some more images here.
Thanks for stopping by and happy shooting.