That MK3 has a little bit longer blade length and S30V steel. Simple design, nice blade shape, nylon sheath. Looks like a great all around hunting knife. Would be my ideal specs for my carry knife on deer trips.
Do you mean KOA Alpha Wolf/Muskrat combo? If so, I just got the magnum boar hunter in D2 and the blade steel is excellent. I haven't "broken it in" yet, but it's shaving sharp and I'm happy with it for the price. The suregrip handle is grippy and comfortable, but I prefer micarta or similar. I like their combo sets for big game hunting and the leather sheaths they use are good as well. I think the muskrat is 440 steel though, which should be fine for caping and fine details, but I haven't heard any feedback on it. It looks like a great little knife, even for small deer and other mammals.
The other option is just get the two knives that you want and have a custom sheath maker make you a nice customized combo set that has both sized knives that you like to carry.
Just my .02.