Can anyone tell me if there's a narrower date line for the grooved handle style skillets than the 1944-1957 range? I think I read of a shorter production period, but can't remember what it was or where I (might have) seen it. I've been putting together sets of them, minus the unicorn number 10, and would like to have accurate info for the fact sheet I provide with a set. Also, did the groove have a purpose, like keeping the handle cooler, or was it just a design feature. Thanks