I replaced my valve stem seals but like you said, I don't know if it was really necessary. IIRC, it sounds like you are doing the springs right.
The 'Mule' 96 2WD F250 EC/LB auto PSD, semi-retired.
The 'Old Gray Mare' 97 dually cc, rest in peace. To be resurrected by a fellow FTEer!
The 'Babe the Blue Ox' 97 dually EC, all stock, for now!