So after a little internet research I've found that VW started making the MK4 Jetta in the middle of 1999.

It just so happens I recently bought a 1999 Jetta. How can I found out whether my car was made before the MK4 threshold or not?

Thanks!

 

The Jetta was introduced in 1979. VW Jetta History

Your 1999 is the third generation. mk3.

 

My Jetta actually is an MK4. It was made in November of 1999, which is after the date they stopped doing MK3s. Thanks anyway.

 

Well the mk3 was 1992-1999 the mk4 was 1999-2005 so you could have an early mk4.