I am doing a 3800sc with a getrag 5 speed swap on my ‘84. That car is a 4 speed now. I’m looking to just modify my shifter. I’ve tried to do as much research on this as I can but don’t see too much on this topic. From what I see, the only difference between the Fiero 4 speed shifter and the 5 is the 4 speed reverse lock out. So would i just be able to remove the lock out and then boom it’s a 5 shifter.?
Any input would be greatly appreciated!

Yes, just remove the spring loaded reverse lockout mechanism (several ways to do this) and hook it up to your 5 speed.

My first isuzu swap in place of a 4 speed reused the 4 speed shifter.