The code you reference is
Free to use, but not necessarily
free. At the bottom of the page, you'll see:
This page was last modified on 5 November 2012, at 23:58.
Content is available under GNU Free Documentation License 1.2.
And it includes a link to the GNU Free Documentation License 1.2
Read the GNU documentation license to see what you need to do with attributing the code and providing any changes you may make.
In the US, design patents are only valid for 14 years after granting. See this USPTO link.
The Wikipedia article on Linear congruential generator indicates a number of implementations and their coefficients. It also includes a reference to Microsoft's implementation within Microsoft Visual/Quick C/C++.
Those compilers had their origins in 1983 or 1993, depending upon which you look at. Either way, both are well past the 14 year limit for patents.
You also don't know that MS performed the research in order to discover those coefficients, nor that changing the coefficients would be sufficiently novel as to merit patent protection. The LCG algorithm has been around for a long time. Given that there are a number of sets of published coefficients, it's pretty safe to assume that they aren't protected through patents.