Accuracy, sure. You can very easily parse and see that your accuracy is capped(though still, not many people do, given your blood pacts aren't an accurate reporter of it and nobody cares to let an avatar free melee during bolster buffs on T4). A basic SMN is visibly under cap on Albumen, sometimes even with shiromochi(which is already sacrificing attack vs akamochi).
Attack is entirely different, have you logged anything to indicate it? You can fall back on frailty's wiki numbers, but my experience(corroborated by Ramzus) is that defense down may have a global cap on t4(and probably other mobs). Even then, without a base defense # to compare against, it's pretty hard to conclusively state attack is capped based off of existing test material.
For practical results, you could certainly figure out how many hits each volt is and use that as a baseline to established capped or uncapped attack, but I haven't seen it done. Seems like a whole lot of unsubstantiated assumptions to me.