You can probably do it, but it's not necessary.
Get a can of brake parts cleaner and just blow all the old oil and crud out of the inside. Then, spray the same areas with WD 40 to get lubrication and protection into the gun's nether regions, as the brake cleaner will remove all the oil from inside the gun. Be very careful not to get this stuff in your eyes, and rubber gloves are recommended. Dry the gun thoroughly, and use a good oil like Quick Release on/in the gun.