sig p 226 serial number question

Hello, Guys!
I am new to the forum,and have a question about a recently purchased used Sig P 226 9mm pistol:
The serial number tables & proof marks indicate a manufacture of 1995,but the slide says"Made in west Germany" on it.
I am pretty sure West Germany did not exist after 1990,so can anyone tell me what the deal is?
Is it possible that the slide was made many years before,and simply not serial numbered and Proofed along with the frame until 1995?

I am a big Smith & Wesson collector,and I know that they have been known to do this with firearms that they manufacture,so I wonder if Sig Sauer did the same thing at some point..
Thanks for any help in advance,

You may try posting your question on sigforum, alot of sig info and good people to help with sig questions.