Cinstone the link goes to a gate not to your actual posting etc .
Is your Stutzen a tap loader ? and is the spare stock 'different' to that on your action ? With no 'dimple' to the left hand side .
If so its def a RB2 style stock .
[ which incidentally has a longer inlet than that on your complete Stutzen ]
If reverse of above then if a dimple present then its for an earlier tap action .
Unless its walnut and you have a Centenary stock -sim to the first tap action Stutzen .