Adding to your observations...
I made a scan of the #20 from the 2012 Unitrade catalogue AND, another scan of my own copy of #20.
First 2 pictures are from the 2012 Unitrade catalogue
The next 2 are from my own used #20 and
we have Coriandre samples
About the bottom left hand side :cat. copy : hairline touching the frame, also looked with a magn 20x
my copy : The circle does not touch the border
Coriandre': The circle does not touch the border
About the right hand "2" : Coriandre's copy has a broken 2 which is not the case from the cat. copy and mine
Also, the shape of the bottom of the "2" (the tale) of my copy is different (larger, bigger) compare to Coriandre' and the cat.

