The main difference in the Glenfield variants of the 336 were stained birched stocks which usually had impressed checkering, and cheaper and simpler sights.
Often, instead of impressed checkering they used deeply embossed animal images in the grip area, which were, frankly, kind of tacky, but somehow appealing. Kind of like a .22 rifle of the 60s era.
As well, the ramp front sight was replaced with a dovetailed gold bead type. Just as good, and maybe better. The rear sight was an all-stamped steel open sight, as used on .22 rifles.
The changes did not affect their quality, strength, or accuracy.
And, I actually liked the sights and the stocks.