Almost all 40SW P99 were made in Germany. Only a very small number of them were made in the US by Smith & Wesson. To be honest, I have only ever seen one of these US made 40SW and it was on this forum a month or so back.
It is more unusual to aquire a US made 40SW P99 than a 100% German made.
It is more unusual to aquire a US made 40SW P99 than a 100% German made.