Taking into consideration all of the pre 64's I have owned, I have had one give a problem.

It had some sort of problem with the safety not moving correctly. While I am all thumbs with fixing rifle problems, my local gunsmith fixed it quickly and cheaply.

In short, don't worry about possible problems. Those rifles were made to last and have proven it.

Hard times create strong men. Strong men create good times.
Good times create weak men. And, weak men create hard times.