That's an interesting piece.
If the serrations were done at the Busse Shop I'd consider it a variant.
(what follows is my own opinion and the way I judge variants)
I have a criteria when looking at and buying variants.
1) Is it a Busse original or did the Busse shop do the work?
2) How much variation from a regular production piece is it (ie. minor work done, medium work done, or major work done)
3) Is the piece that it is a variant of a current production or discontinued production piece
4) Is it a completely original piece from a regular production piece? (ie what has now become known as a GFD)
5) Is it a full custom piece? (although these may not be considered variants I'll add them in as they are unique and should be discussed in this topic)
6) What is the condition of the piece? (new, used and even the history of the piece if it can be determined)
7) The size of the piece(some of the sizes of variants are more rare than others) and the size in general influences the value.
Each of these points helps me judge the knife (variant) and what the approximate value is. Of course some of these points may become mute depending on the piece.
For example I have an all black Killer B, that has had the choil enlarged. I consider this a minor variant, however, I also consider it rare because it is the only one I've ever seen like it. I also consider it rare because in general the all black ones are more rare. Finally I consider it worth a little more because I know a bit of the history and I know that this enlarged choil was added by Jerry himself. (My understanding is that the major variations are all done by Jerry but some of the minor "tweaks" may have been done by someone else in the shop) Is it worth a tremendous amount more than a regular KB, no probably not, but it is unique.
I also own the Red Cross variant, the one that is now pictured in my avatar.
I consider this a major variant or a GFD, and I consider it worth much more than a regular production piece of the same size. My reasons follow.
1) It is one of a kind, completely original
2) My understanding is that it probably will not be reproduced because of the handle design (straight handle Battle Mistress). Any newer ones will be made from a current pattern
3) It is new, never used(although on this piece this played little in my estimate of value)
4) Jerry made this himself.
5) It is a large piece.
Now, back to your Badger Attack, I would consider it a minor variant(sorry nothing personal
) However, I would also consider it rare as I've not seen many like this (maybe one other) I would not be overly concerned about the use but it would have a little bit of influence in my estimate of value. And at the time this one was made my guess is that Jerry may have added the serrations(this is just a guess, but based on the fact that his shop was smaller and hence he was probably doing more of the unique stuff)
It is also unique because it can not be easily made at this time, since the straight handled Badger is discontinued, you can not get one from the shop like it now. Of course this is all based on the assumption that the serrations were added at the Busse shop. (If the serrations were not added at the shop I actually would consider them as a huge decrease in value) Also if you bought this as a user and just thought it was cool then you can throw all my post out the window. Because if I were buying a knife to carry that would work and look cool, I'd buy that BA in a heart beat.
The above post is just my opinion and probably wrong