Bullitt,
My apologises.. you did ask me about this on the other thread, but I didn't reply.

I'm not overly familiar with this particular model, and haven't really followed any past discussion on the two dials.
Personally, from what I can see in the photos you provide, I would be satisfied that they are both 'good'.

The example with the thinner Heuer shield does look 'better' aesthetically, but the example with the thicker Heuer shield still looks genuine to me.
Also.. I've owned two Ref. 12's from the late 70's, and one had a thinner shield, one had a bigger, fatter shield - and there was a minor difference in positioning of the lume dots, but both were original.

Please note that I've never handled any of these L5100 Silverstones, and I'm just going by what I can see in those pics.

Stewart
- Heuerville