JUDY was introduced and ran along side the MAG series (incl. Quadra) from late 1994 (aka 1995 model) to 1997 (last year of MAG's).
Serials are just continuous and doesn't give details of year afaik.
There are 3 main types of MAG21'
The 1993 MAG21
The 1994 MAG21 where they evolved they improved the internals for a better ride, altered the crown & brace a little and gave them Alu stanchions
The 1995+ MAG21 where they went back to a steel stanchion and removed some notches on the dropouts.
1995 where gold with gold brace
1996/1997 champagne with black or champagne brace, also the V-brake brace version was available.
1994 also had the SL with where same as 1994 MAG21 with Alu threadless steerer and where a green gold colour and Magnesium brace
1994 also had SLTi which where SL's in a clear gold colour and four ti bolt and Ti canti studs.
Serial numbers
27266 through 158841 are 1992 MAG21 or 1992 MAG30
I would believe Mombat/FirstFlight over myself as I left the 'mtb following' around late 1995 and anything after that is modern stuff.