Take care that the alarmed lock, which can becquite bulky, suits your discs.
I have one which, due to its large diameter but very narrow discs, cannot be used on my 1600. In simple terms, the narrowness of the disc means that the pin for the alarm cannot be depressed, so it sounds just as soon as the key is removed.
PS Despite the alarm not bring fitted, the 1600 has not be stolen, so I’ll give full marks to the lock (in absentia) and to the pound of butter in the fridge.