Unusual Plomb tool marking

[bigcaddy]

My dad was out hitting some sales and picked up a few plomb tools for me in the process

Some was pretty standard stuff but this drag link socket has a letter stamp I've never seen before.

If anybody has some input, I'd love to hear it because I can find anything about it online.

 

[Plombob]

That's the fun of collecting Plomb! You occasionally find these markings. Sadly we don't know what they mean. That information is lost to the ages.

 

[Outlawmws]

NR: Non Returnable? Sort of like the "G" on war time SO?

 

[WWIIjeep]

NR: Non Returnable? Sort of like the "G" on war time SO?

Not Rare.

Not Recommended.

Non Reversible.

Navy Rated.
Never Rong.

 

[beatcad]

never rust
no refund
newly refurbished
northern region
november rain