Different IBM Model M keyboard

Hello, I like the IBM Model M keyboard. They are very durable, have a good feel, and I can easily find them cheap. Yesterday, I bought one that is a bit different, However. The feel, isn't quite the same, which really surprises me. It's not particularly bad, just a little different. I don't think it is any newer or older than others I have owned. The big difference is not feel, but color! This one has colored keys! I think it is set up for use with Wordperfect, but am unsure. The Shift keys are green, the alts blue, and ctrls are red. Then some of the other keys are a very light yellow, or creamy color and are labeled for different functions. Each of those keys has 4 functions depending if you press the shift, the alt, or ctrl. Unfortunately, I am missing one blue alt key cap :-( Is this factory IBM, or is it a fairly standard Model M with an aftermarket key cap kit? These aren't just stickers like I have seen before. Chad Fernandez Michigan, USA