I've never heard of and can't find on line a Stealth reserve. Rigging Innovations has a Stealth Reserve PILOT CHUTE, their trade name for one of their spring loaded reserve pilot chutes. Is that what your referring to? What was the context?
Smart reserve is a canopy made by Aerodyne.
So you could have a Smart reserve canopy in a RI H/C with a Stealth Pilot Chute.
The Stealth Reserve is actually a Smart made by Aerodyne, they called their new reserve, after the Tempo, a Stealth and then made a corporate decision to rename the reserve canopy a Smart. Some early Smarts were sold as Stealth so if you have have a Stealth Reserve then pack it as a Smart as it is the same thing.