Just so you know, the Mamba II and the original Mamba are not the same blade profile. The II has a wider blade with a more pronounced belly. That's not to say that the II is not a good knife....I like mine. But I prefer the profile of the I.
Quick model list run through:
Original Mamba, Blackjack Knives
http://blackjack.0catch.com/pages/mamba.htm
Remade Mamba, called Evolution I, Bark River (mentioned in above link)
New Mamba, Mamba II, Bark River
The Mamba and Evo I, basically same design. Mamba II, different blade profile.
Be advised two things: a lot of the original Mambas were stainless, all made in Japan. Also, per Mike Stewart, the Japanese factory apparently continued to put out stainless Mambas after the model was discontinued by Blackjack....not fakes so much as "unauthorized". Essentially same knife, but don't pay any kind of collector price. Pull the scales; if the tang says "Japan", you have a stainless....probably won't be able to tell if it's "official" unless you have the box it came in.
Very few "black Mambas", officially all CS-51 and all made in U.S. However, I have one that says "Japan" on the tang. Always pull the scales. Caveat emptor.
Just my opinion, but if you want a chopper, you want either the CS-51 original (US made) or the A2 Evo I.....if you want the earlier design.
The A2 Mamba II will serve you just fine as a chopper.