Price
These aren't typically wear items, but after 30 years they're not exactly new, and they can get damaged by multiple timing belt changes. Hedge your bets and get a new one.
For small nose engines only. That's only 1.6es before mid-91. On a 1.6 engine, count the number of slots on the face of the crank pulley - eight is a big nose, four is a small nose.