Native M or LTM + Adapter ?

[srtiwari]

Just acquired a near mint Summaron 35/2.8 (without goggles) sold as an M lens.
When it arrived the mount looked like a separate adapter, and itself has the tiniest screw that I removed 🙂eek🙂 , but this did not release the adapter. The screw itself is too tiny to actually hold anything substantial in place, so its function is unclear. In a native M mount, is that screw present ? I am not about to try and remove any of the 3 screws on the body itself. Any thoughts and /or suggestions ? I may just send it to Youxin or Sherry to do the right thing.
If it is an original screw mount, great, since these are rarer...

 

[EZfan]

Early one is dual mount and it does have a tiny screw with minimum focus distance of 0.7 meter. The real LTM Summaron has a minimum focus distance of 1 meter.

 

[srtiwari]

Early one is dual mount and it does have a tiny screw with minimum focus distance of 0.7 meter. The real LTM Summaron has a minimum focus distance of 1 meter.

Thank you for the Info. It is an early one then (169xxxx) with a 0.7 minimum focus, and I have put the screw back in. What exactly does it do ? Is the adapter then removable (for LTM use) ?