It doesn't look like a real early GHS Stock. If you could post a pic of the clip release cut out, butt of stock with buttplate removed , bottom of pistol grip and trigger group pads it would help in identifing it.
Also a pre war SPG would have a long channel and SA also supposodly used the SPG stamp on some postwar SA rebuilds. In any case SPG vintage could be determined by looking at the buttstock storage holes..
From the one pic it is a short channel stock. Late GHS's were short channel and all GAW's were short channels. If the clip latch cut is slanted and there is a small letter or # in the barrel channel than you might have a GHS. If no mark in channel and clip cut is straight and you can see a faint tiny ord wheel on bottom of grip than you might have a GAW stock.
The pictures just don't show enough details; The milled ferrule really doesn't mean it's an early stock, it's not uncommen to see them on later stocks even post wars that had them put on during a rebuild.
Hope this helps and not get ya more confused