http://www.castbullet.com/misc/tdown.htm
If you do it yourself... make sure you have a good set of GUNSMITHS SCREWDRIVERS.
I have taken a few pre war Winchesters apart... about the only part that causes real trouble is the magazine tube. Those need to be swabbed out every 80 years or so. I bet your 50's version could be cleaned well enough by cracking the action open and going after the innards with spray solvents, rags, old toothbrushes and fingers.
When I work on a Winchester lever that needs a little more attention... I pull the buttstock.. hose out the guts with a good solvent and blow it out with compressed air. Oil up the moving parts and go shooting.
Amen to that.
How about the Winchester 1897's? I had a couple about a year ago come to me that had been sitting in an attic for about 70 years and they were dang near welded shut... they sure cleaned up well, but boy did it take a lot of elbow grease.