Over the past three decades, I've handled and/or projected original 35mm year-of-release prints of the following U-I 1950's B&W features: Abbott and Costello Go To Mars, The Glass Web, The Land Unknown, The Mole People, The Incredible Shrinking Man, Abbott and Costello Meet the Keystone Kops...
Bruce is 100% correct.
Several years ago, we ran an original 35mm print from 1957. I was truly surprised at the level of grain throughout the film. The opticals were especially noisy.