Early '67 Sub-frame date code?

[MyRed67]

   I have been cleaning up my Early '67 Sub-frame, (no holes) in front horns.   I found some sort of a code, (maybe just partial) on the ouside of Pass. side frame rail.   I think it might be a Date code???  I am attaching a sketch of what it looks like, as I don't know if I can get a clear enough picture.  Any ideas???

[ccargo]

Is it stamped into the steel or painted/stenciled on the steel?

[MyRed67]

  It's stamped into the steel.   The O R is 1/4" letters, and the 142 (or maybe I 42) is 1/8" letters.   If it's I 42, it is very similar to other date codes I have found on the car.  The doors are H 42 and H 43.