I'm sure that would be the general rule - within reason. But with weapons, in our system it was slightly different according to my colleague WO2 Jock xxxxxxxxxx. Off the shelf 'non service pattern' stuff was rigidly tested to ensure that it was suitable and safe. After all, it's no use having a, (from my knowledge.....) say, silenced SMG with such close tolerances that is incapable of operating in a dusty climate or something that is so fragile to the point of being unreliable. But you get my drift. That's why there is always a xxxxxxx xxxxxxxxxxx xxxx and similar available for advice