Different versions of the new Elmar-M 50mm f2.8

Today I have seen for the first time original version for M6J, with focusing tab. Before I have seen only silver and black versions without focusing tab. Interesting how many different versions of the same lens are produced by Leitz .
I am wondering how much more expensive the version with focusing tab is...

The M6j version looks like the older 50 2.8 Elmar, complete with focus tab. I had a late production example from 1969 (very late). Mine also had infinity lock. Nice lens, which I shouldn't have sold.

Is this one has long focus scale and LTM mount? it is kind of not so good on M.
Any lens with too long focus travel is so-so on M.
I do not regret of selling my Elmar-M 50 2.8 due to absence of focus tab and long size, but I think it is possible to add focus tab on it.

I use LTM Elmar on my M3 when I want something small, and DR summicron is too big. Of course I have not so convenient f stops and filter issue, but small size is unbeatable.
But I have only old lenses in M mount, and sometimes I wish to have more modern look, and right now I am considering new Elmar-M, or 50mm f2.5 Summarit.

Elmar-M 50 has best Tessar rendering I ever seen. I had black one and sold it.
It has flimsy feel and was way too long with filter and hood for 2.8 lens.
I don’t know if 50 2.5 has any rendering at all or it’s predecessor Color Skopar 50 2.5.
Best lens for M3, IMO, is collapsible Cron. It is same size with Elmar-M 50, but rendering on BW is just perfect. And better build. None of the later Crons are close to it, they just sterile, next to flat on bw film, prints.