Diferences?
 

Year by year, Were there any difference, either cosmetic or mechanical between a luger made in Germany and one made in Switzerland?

The first Swiss Lugers were made by DWM. Later in their contracts, DWM provided finished parts and the Swiss did the final fitting and finishing of the pistols.

By WW-I, supplies from Germany were unavailable since they were diverted to the German war effort, so Switzerland licensed the design and began fabricating the Lugers completely at Bern by 1918. Later starting in 1924, Bern started working on a cost reduced design that they made at Bern using parts manufactured by SIG at Neuhausen continuing this through 1948 when the Swiss changed to the SIG P210 pistol. Here are examples from each major era of Swiss Luger:

Note that Mauser made a small number of Lugers for the Swiss, but there were never large contracts for those pistols.