[Leica] Help with an old Summicron 90mm

[banacloj at mac.com (Juan Gea-Banacloche)]

Hello,
I am a relative newcomer to the list, and I have only posted a couple 
of times before, asking for help (and getting it). I am a Spanish 
physician, but I live and work in Bethesda, MD. I started in 
photography in 1976 or so, and a couple of years ago I decided I would 
like to take pictures with the cameras I had wanted to own back then in 
the 70s. After starting with a Leicaflex SL a couple of years ago, I 
finally got a Leica M3 last year (which, of course, was not being made 
in 1976, but had become a "dream camera" for me back then). I have been 
using "classic" (i.e., inexpensive) lenses, shooting B&W and developing 
in XTOL (the XTOL I owe to this list: thanks).

I recently got what I thought was a nice old 90mm Summicron for the M 
[I guess a SEOOM (or maybe a SEOOF-M???), s/n 1742368]. When I opened 
the box, I was disappointed to see it cannot be mounted on the M3-- it 
has a Visoflex mount. However, the drawing of the lens on the side of 
the box shows an extra ring with the M bayonet. That this ring was part 
of the original lens is suggested by the size of the box and the marks 
on the velvet lining inside the box.

I would like to believe the lens could be used either on the Visoflex 
or mounted directly on the M3 by removing or adding this hypothetical 
ring. Does anyone know if this is the case or not?

If this is the case, does anyone know which is the Leica code or number 
for the ring? It is hard to look for it without knowing that (hard to 
post a succinct WTB message without that information).

Thanks in advance,

Juan Gea-Banacloche