whould these heel guards even fit with tusk nurfs?

Those should work with tusk nerfs, the tusk ones mount in front, where-as those heel guards on the back.

I have a folding shift, but you should measure the stock length one to see how close they are
 
I dont think they would hit, if they did, you could cut off the rounded part on the back of the nerfs, because there is still a flat piece running along it, i have a set...
I could sell mine for a lot less than new ones if you are interested, pm me

The hand guards look really good, its got the metal piece running through the whole thing, pretty strong there.
 
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if/when you get a message, it will say "notification" under your name at the top right of the page.