Harrison Radiator Question

[RonNova396L34]

rpoZ11
Would putting a piece of paper over it and then running a pencil across the paper lift the number? Kind of like tracing a penny under a piece of paper? See if that works. Otherwise maybe shining a different colored light over it in the dark like a blue light or a red light like a "laser pointer." Sometimes shining a flashlight at a real low angel across the item in the dark will work. This works nice for me at work in the dark.

69L89396

If that's the case, "F" (June) would also be right for my August 69 build date??

Ron