Please help identify this mount?

[Max Carnage]

Hello. Very nice forum you folks have here!

I've bought a lens very cheap, an Isco Göttingen TELE - WESTANAR 135mm f3.5. Now I need to decide how to mount it on my Olympus 4/3rds camera.

First, a few photographs. The lens:
http://tinyurl.com/yhz3uul

And now the mount:
http://tinyurl.com/yhkz5rw
http://tinyurl.com/yzjr5vj

The seller said it was 'unidentified mount'.

Now, it's unusual. It's a bayonet mount, but the lens joins from inside the bayonet ring (female I think) rather than outside like most lenses. I first thought it to be an Adaptall lens without the adapter (see, I'm new to this. Only Tamron made Adaptall). Now I'm wondering if it might be a Canon FD or FE? Or even be missing its mount, with the bayonet I see being a manufacturer-specific thing that allowed them to join this lens to several mounts (google photos of this lens with M42 and PK mounts show another thin ring attached to the mount end)?

The internal measurement of the bayonet ring is 43-44mm as best I can measure it (ruler+eye).

Any help would be appreciated. If it might be FD, I'll try an adapter. If not, I plan to give it a make-over, butcher a spare 4/3rds adapter and screw it on as a replacement mount.

[Max Carnage]

[/me being useless]

[dnas]

[Max Carnage]

Thank you dnas! c",)

[Max Carnage]