They certainly do look like Nill grips, which Wischo (the German distributor of many S&W pistols made for the international market) installed on their pistols. If you remove the grips, the name "K Nill" engraved in script will be on the inside of one of the grip panels.
A beautiful pistol from the Performance Center. "Target Champion" seems to be a favored European addition to different calibers of S&W pistols sent to Wischo, which had the engraving done by Smith before shipping. Here's a thread that shows one that stayed Stateside but does have the WPC prefix and all the features of yours except the Nill grips:
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=466664804
The Standard Catalog of Smith & Wesson (p. 343) lists product number 170038 as a Model 845 with 5" barrel in .45ACP for Wischo. If the box came with your pistol, that product number is probably on it; I don't see any other product numbers that are that type of description.
Here's a good thread on the Wischo "Target Champion" and other pistols and revolvers, and also provides production numbers on your model:
http://smith-wessonforum.com/smith-wesson-semi-auto-pistols/346134-s-w-845-wischo-history.html
And there's also a photo of the same model as your .45 Target Champion at post #8 in this thread:
http://smith-wessonforum.com/smith-wesson-semi-auto-pistols/416582-745-vs-845-vs-945-a.html
In the U.S., this model was called the 845 .45 Limited, or ".45 Limited," a limited production for Lew Horton Distributing with alpha prefix MPC from 1995 to 1997. It came with the Xenoy grips. It was followed a year later with the 845 Model of 1998 (misprinted, 1988 in the catalog) in a run of about 150 with alpha prefix SDN -- for S&W stocking dealers, I suspect.
