As a Brain fan, nope. We learn about Fourfold from the tournament with Gazef right before the Shalltear encounter, with Brain first using it against her in Volume 6
Actually, there's evidence to the opposite
"Even a hero — one who had surpassed all other humans — would have had trouble blocking that attack. Mortals, wrought of weak flesh and bones, would not be able to even muster up the stamina to defend against it. This was an inhuman blow.
But Shalltear Bloodfallen was well above humanity herself, standing in a league of her own that nobody could ever hope to exceed. To someone like her, those four simultaneous strikes were little more than a snail taking a stroll in the sun.
Shalltear snorted at him as her left hand moved faster than the eye could see. A sound of metallic clashing rang out through the night air. What had happened was that the simultaneous deflection of the four strikes had blended into a single sound.
All four blows had been repelled, leaving her untouched."
In fact the actual gif we use for Nail Clipper has her moving to deflect it
after Brain draws his blade: Edit, wow I love how the VS wiki gifs/images/videos never actually link correctly when using them LOL
As for the Fourfold Slashes being Lightspeed or not, that a different argument though I don't see why they wouldn't be since from what I recall and am currently re-reading the only difference mentioned between them is not speed but rather accuracy. As both moves are stupidly hard to land however Fourfold is the easier of the two.