Again, wrong. If You have EVER opened an Amiga 500 floppy, you could see the sensor. The sensor that is not present is tho one that detects the other end of the head motion, that is usually track 81, on better drives 82.
Disclaimer: I have no idea what type of floppy drive an Amiga 1000 uses, I never had A1000.
But I do have an Amiga 500 and Amiga 1200, both in working order, and a pile of external floppy drives, and internal floppy drive from Amiga 2000. Every single one of them has 0 track alignment sensor and uses it. The only way to get the different click sound is to deliberately ignore state of /TK0, pin 15, and to order head position to decrease. It is possible, but will not occur unless you disconnect the sensor.
If You need an photo of Amiga floppy with sensors, e-mail me on junky_space_fee(a_t)yahoo.com