M721 "Patents Pending" ???

[JamieADLLS]

I noticed on my M721 the barrel reads "Patents Pending" where I've seen others have a patent number stamped. It is the E SS gun listed in the "date code" thread.
Has anyone else noticed this? Does anyone know when the patent numbers started showing up on the barrels?
By barrel date?
By serial number?

Curious minds want to know!

[Rem725]

I just checked two of mine, one from 1955, and a transition 1958 rifle. Both have two patent numbers plus "others pending".

Jamie, your sight things are on the way.

[JamieADLLS]

Thanks Rem!
I am rather curious about this patent# thing and I'm hoping others will chime in. It might help us all identify the oldies more quickly when we're out scanning in pawn shops etc.