Hi Tony and welcome to TRS~!
As long as they are both the same cab style (reg vs ext) then it should be a direct swap since the cabs from 98 up are similar.
The only thing you may need to change is the harness that runs to the doors to power the windows and locks but I think they pre-wired everything in so they could outfit any options...but I could be wrong.
Thing to do would be to get the whole truck and then you can swap whatever you want as needed.
The only thing you really need to be careful about is the PATS (passive anti-theft system) but if you ware swapping in the whole dash that would fix it all in one shot...this was installed on Rangers built between 1998-2001 so those two years (99 and 98) are in that group.
If you run into problems there are ways to work around them...but the best thing is to swap out everything needed like the dash and the steering column...but if you are swapping interiors to make them a different colour then that would be part of the swap anyway.
I couldn't find anything in the Tech Articles on this but you can learn more from the following link:
http://www.explorerforum.com/forums/index.php?threads/everything-you-wanted-to-know-about-pats.234975/