More or less.
It’s absolutely canon for MWO.
It’s probably, leaning toward is, canon for CGL.
But let’s be adult here and realize that these are two different properties, two different licensees who work together but are ultimately seperate. So while we can say “the Roughneck is canon,” we can’t use the Roughneck artwork. Which puts it in a greyer area than most other things.
Basically “yes,” but for anything like that, be it the Sun Spider or the Aurigan Coalition, you’d really have to wait to see what CGL does with it to see how it fits in “CGL canon.” Because while we want (and try) to see everything BattleTech under one umbrella of canon (thus, Randall’s ruling), it truly is more like a Venn diagram.