A few years ago I bought a used Kimber, a Custom Covert II. Never really got around to using much like the majority of my handguns.

My question concerns the spring weights. The slide on this pistol is next to impossible for me to pull back unless I grip the slide overhand with my left hand and push the frame forward with my right hand. I'm not Charles Atlas by a long shot but man it is hard to manipulate. Do the Kimbers come with up-rated springs?

I have a sample size of one and it's an Ultra Crimson Carry II but it doesn't seem any harder to rack the slide than my STI.  If it's that hard to manipulate it's possible that whoever owned it before you installed a heavier spring for some reason.

Don't use Gold Dots and Wilson Combat mags.  Fucked mine up.  I hope you have nothing but a quality reliable gun.

cock it first helps.

Being that it is used, the previous owner may have changed the springs.
From the factory it is supposed to ship with a 16lb recoil and 21lb main spring.
Springs are easy to change, at least the recoil spring is. The mainspring will take a bit of mechanical aptitude.
Try cocking the hammer first before racking the slide like another poster said. If it is still difficult, I would swap the recoil spring with a known 16lb recoil spring.