I picked up a CD 122.4 this past weekend because my memory didn't remember an embossing exactly like this one. as follows:

(F-Skirt) PYREX/T.M.REG.US.PAT.OFF. {Closest is the 070 but note no Made in USA on this side (R-Skirt) MADE IN U.S.A./PAT.APPD.FOR (Dot) M C (nothing mentions letters afterwards, certainly not MC

Inside of skirt is threaded.

Is this just a one off or is it valuable, unique?