1944 Long Branch No7 Marking

Hey all,

I was looking over a 1944 Long Branch No7 trainer and noticed an unfamiliar marking. Does anyone know what the "2" stamp of the barrel reinforce flat means?

Please see the photo below.

https://www.milsurps.com/images/impo...538faa_b-1.jpg

https://www.milsurps.com/images/impo...403def_b-1.jpg

Thanks,
Kevin

My 1946 C No7 rifle has identical markings--I hope somebody knows what they are.

Attachment 139334