[Leica] Summicron 90 versions

[s.yoder at verizon.net (Stan Yoder)]

I dunno how accurate Sartorius is with s/n ranges, but he says:

v.2 is from "approx. 1,651,000 to approx. 3,013,000."

v.3 is from "approx. 2,800,000 to approx. 3,750,000."

Thus an overlap, yes?

Quoted weights are 685gm and 410gm, respectively.

I notice from photos that v.2 has a scalloped focus ring, while v.3 has 
a smooth one. Is that a reliable indicator, or not?

Bottom line: would an example w/ s/n 2,750,xxx and a smooth ring likely 
be a v.2 or v.3?

Thanks in advance for any help.

Stan Yoder