Dating a BSR Century Series Skillet

I am currently working on a few Century Series skillets and am trying to get a handle on the overlap period between Red Mountain and Century Series from 1957 onward. This skillet does not have the "MADE IN USA" at the top but has the "NO 8" and the measurements below. Here is another hint: The cooking surface is very smooth. My guess is ca. 1960.

I'd bump it up just a little - ca. 1962. I'm under the impression there was quite an overlap in the 50's.

Hilditch

Here's another curiosity. I have had 2 Red Mountain number 12s so far. One had the glassy smooth cooking surface but the other looks like a Lodge of late. Of course one could have been the true Red Mountain (smooth) while the other was a bit later. How far am I from getting a handle on our beloved BSR?

according to:
http://www.modemac.com/cgi-bin/wiki.pl/Birmingham_Stove_and_Range
it was made between 1966 and 1968
I have two pans from this same time span.