Original 59 magazines have a metal floorplate with a S&W marking on them. They will work. Far easier to find are the genuine S&W 3rd Gen magazines, most often found with the yellow follower. These have a plastic floorplate with a half-moon cut-out and a tiny "Smith & Wesson" printed inside the cut-out.
Mec-Gar also makes high quality magazines that absolutely work and every indicator is that the "Original Equipment" brand magazine is wholly made by Mec-Gar. Please do note that this is kind of a sneaky (smarmy) move by CDNN or Mec-Gar (whoever came up with the idea...) at least in my opinion, because it implies that these magazines are OEM when in fact, they are not. HOWEVER... the price is decent and the magazines are fantastic.
Triple K, Eagle, especially Pro-Mag? Avoid these like the absolute plague that they are. These are the best choice for all manners of FAILURE drills. With the exception of failure drills, it's better to pull a $20 from your wallet and light it on fire than to purchase these magazines for a S&W 1-2-3rd Gen pistol.
