Yeah not only does skunk usually have high phenotype plasticity just like your saying it's a strain that can also throw out crazy profiles that are all over the show as well so it's not just the grower and environment etc it's very varied to begin with more so than any other strain ime
I think it depends on the line. I found sk#1 to be stable in the sense that you could tell a skunk plant from another strain, fairly homogenous, but you'd get big, small, better sweeter terps on some plants, some more compact like Afghani, but all having the same branching and basic terps. It wasn't as much of a spread as what I am growing now.
Also, the bracting didn't change that much, you'd get better ones of course, but all had bracts that were the same in size and in the bud structure. I'd say medium/ small bracts. And some plants were average. Some were more resinous. And some had cherry terps.