Age of Westinghouse Standard

[90grad]

All,

I'd like to know if there's a way to tell the date of my Westinghouse Standard Ice.  I know it's an earlier model, due to cap catcher.  Also, Steve Ebner told me on the early models, the word "DRINK" is lower than on later ones.  On the liner, the following is embossed... W-RRDT

I've got no clue.  Any ideas?