Mike's right.
The original AK-47 does have three settings that one can choose from on the right-side selector. Top is safe, bottom is semiauto or "single shot," middle is full auto or "hey, where did all my ammo go?". Later military versions sometimes have a fourth selector setting between full and semi that allows it to fire 3 or 4 round bursts. On all variants, the selector lever makes a very loud and distinctive "KLACK" when changing from one setting to another.
On the civilian semi-auto only versions, there's only two settings. Top is safe, bottom is semiauto (some say "off" and "on"). It still makes the KLACK noise. Just about as distinctive as hearing a pump shotgun or rifle action being cycled, and just about as effective at making an uninvited guest leaving your darkened house in a hurry at 3 or 4am. The AK variants that are shotguns make a moderately loud click, not the characteristic KLACK when turning the safety off. They do KLACK when you turn it back on.