Planes for fs2002 pretty much have to be constructed with GMax or to Gmax specifications.
I think you meant 'FS2004' John ;) :D
FS2004 *generally* requires GMax or FSDS2 construction - it really depends on how complex the model is.
& remember John's tip - when installing older aircraft - ignore the warning. I have found several old models constructed with the original 'FSDS' (which is version 1.*) work just fine in FS2004 ....
Simplicity is the ultimate sophistication. – Leonardo da Vinci