If you are going to sew slowly and NOT do a lot of sewing the older original resistance controller will be fine, if you sew a lot and fast the old controllers get very hot. I sew barefoot in the summer and they can get so hot I have to pull my foot away...FAST. When we have removed some knee controllers I have seen large brown scorch marks on the tables where the controllers are attached to the inside of the cabinet. Hubby and I find we have better speed control and no heat with the newer electronic foot controllers.
Unless we really want to keep a machine in all original condition we always trade out the foot controllers and usually update the electric cords and adapter plug ends for more modern ones. It isn't that hard. There are quite a few tutorials on the internet to follow. I have three of the 319W's and I like them very much.