Here's my question
I purchased an 89 gt with an automatic to 5 spd trans swap
I noticed that the reverse lights don't come on when tranny is in reverse
I checked to see the reverse light switch and its there
Was there something left out during the auto to manual swap?

 

Check for a bad fuse, blown bulbs, or it could be wired wrong. If it is not any of that take the 2 wires of off the switch and jump them and see if they work.

 

most likely they didn't hook the reverse light wires up from the PRNDL switch to the reverse light switch