Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
No, originals are 3 pin, modern day replacements are 2 pin. Just leave the green earth wire unattached.
IIRC you need to connect the remaining two wires the right way round as the terminal markings might be different. I seem to recall having to reverse the two wires to get mine working - if its an electronic unit you can blow some units with the wrong polarity - worth checking the markings carefully.With the 2-pin units they fit Positive & Negative earth vehicles hence the need to check.