Yes...but unless you're getting ready to mount a serious racing effort you probably don't need to be concerned with it. FYI here is the spec from the MRA rulebook. You can find the whole rule book here:
http://www.mra-racing.org/PDF/2007_MRARulebook.pdf
MRA specifies .032" diameter wire twisted at 8-12 twists per inch. You should always wire the bolts so that the wire is putting tension on the bolt in a tightening direction.