This gun was a GI bring back from WII so no import stamps. You are correct that this is a rarer variation. The only pistols from WII that get import stamps are the WII P.38's captured by the Russians. These were released from Ukraine in Eastern Europe in the 1990's and handled by FEG for import to the US. Also the post war P.38/P-1's the were imported post 1968 have import stamps.
As far as Sauer and Sohn in Suhl Germany goes post war the US 11th armored division occupied Suhl for about 6 months then the area was in the Russian sector post war. The Russians converted the Sauer plant to make the Fortuna typewriter so after WII the pistols we have are all there is. No more Sauer pistols are made at the Waffenstadt Suhl. You have also have to realize the only 10% of the pistol prodution was in Western Europe the other 90% went east and are lost forever.
The picture below is from an import by FEG of P.38's their original crate. Originally taken by the Russian's from the Walther Plant post WII and taken to the Ukraine. In the early 1990's the Ukraine government in need of cash sold off stocks WII captured weapon's. including the crate pictured.http://p38forum.com/forums/picture.php?albumid=5&pictureid=150