It depends what kind of slide you have weather you need a slide lock or not. I have a small sofa slide which has no support at the top to keep it tight, so it came with and needs a slidelock. Without the slidelock the top can slightly move in and out during travel, stressing the components and making for a loose seal. If the slide does not seal completely at the top when retracted then it could need adjusting, but for now the slidelock should bring it in to the sealed position.
2004 Chevy 2500HD Crew Cab 6.0l, 4.10r
2010 Jayco Jayflight 28BHS
Reese Strait Line with Dual Cam
P3 Brk controller