Using zipper to date sweater, can't find one similar

[Birdie]

Hi again! Everyone was so helpful the last time I posted a question so I thought I'd give it another go!!
I have these fantastic cowichan sweaters, two of which have a metal zipper that reads "CC OL AA TR SK". I have never seen this zipper, and googling all these random letters is getting me no where! Anyone have any helpful info about the zipper??
Thanks in advance (& sorry the zipper pics aren't the best!)

 

[retro ruth]

You need to read it vertically. The zip says Coats Clark. In case that helps.

 

[retro ruth]

Ah this the company:
http://en.wikipedia.org/wiki/Coats_PLC

 

[Birdie]

Wow! You are totally right.. what a puzzle huh? haha I never thought of reading it that way