Lock, stock, barrel
This refers to the parts of a rifle: Lock, such as Flintlock; stock as the wooden stock and the rifle barrel. So, if you bought something lock, stock and barrel, that meant that he accepted the whole thing or the whole story and not just a part of it.
Lock, stock, barrel
barrel, stock, action.
It depends.. if you have a carbine length barrel and will be using it on a rifle with a carbine length barrel, then yes. If you took it from a rifle with a rifle length barrel, and are putting it on a rifle with a carbine length barrel, then it won't function properly.
Receiver, stock, barrel, sights
Barrel, action, stock
Stock, action, barrel
On a rifle, it is the part of the rifle your non-dominant hand holds to steady the barrel.
Lock, stock and barrel
the stock is the wooden part that you hold against your shoulder, the trigger mechanism and the barrel are attached to it.
Basically they are the same. But a long Barrel and a long shoulder stock make a gun a Rifle.