Yeah, I thought I saw that. I just wasn't sure. I've run some loose guides before. I've done a LOT of reading about knurling too. Enough to change my mind about it. I think it's beneficial......AS LONG AS you run "some type of" roller tipped rocker. I say that because the knurling does remove some surface area and as a result, they will wear sooner, unless a roller rocker is implemented. As long as you run rollers, I believe they will last virtually forever at that point, because that's about the only benefit rollers give, IMO. They just about completely remove the side loading and wear from valve stems and guides. Well worth their expense, IMO.