Actually NO..white lithium grease is just that 'grease'
Grease will attract dirt, gum up, cause abrasion.
In the owners manual for your slide out you will probably find a statement not to use grease.
A good cleaning with wire brush is all that is needed.
But if you want to use a lubricate on the rack/pinion after thoroughly cleaning and wire brushing a little coat of 'dry graphite spray lube' works. It goes on wet then completely dries and does not attract dirt.
On the piston arm.......just wipe down with a clean dry cloth.
For the slide out seals/wipers.....baby powder/talcum powder