I do not recall seeing those marks on Walden stuff.
Thorsen did that. (the two dashes can also be seen on SOME Giller product (fifth image in string middle of image.)
and
Proamerica/KAL
and
National Tool out of Dallas.
ProAmerica manufactures most of its product for private-label accounts. (ProAmerica/KAL/Emporium Forging = all one and the same)
National Tool manufactured ONLY for private-label accounts.
The private-label KLEIN sockets are not marked with either part number or manufacturer's name.