Yes its a job you can do your self if you are handy and have the right tools.
Pillars are installed for a solid place for the action to bolt to. They are installed between the bottom metal and the action. So when you tighten the action bolts you do not "crush" the wood. Over time action bolts will compress the wood.
Most of the time the are put in for the solid mounting surface and bedding material is installed to hold the action in the stock tight and perfect fit.
With that out of the way. It is much easier to install with a milling machine or at least a drill press. You have to open the action bolt holes up to accept the oversize pillars. then they have to be bedded in.
Pillars can be made or bought. Check out this sight..Score High Gunsmithing, Muzzle brakes, Bedding Epoxy and Pillar Bedding kits
With all that said, I have no idea how the Marlin bolts to the stock and pillars may be more difficult to install.