Summary:
there are 5 1/72 Alpha Jet kits. Airfx, Matchbox, Heller, Fujimi and Starfix. From now one I will discard the latter!
Of these, the Mtatchbox kt represents the engineering mock-up, and as such is inaccurate for a real Alpha Jet (Something MB did with other kits as well - notably the Lynx)
Airfix and Heller are of similar age (Something in my mind says the Heller one is an early version, but until I find the kit I can't comment) - both have raised panel lines. The Hellerr one has better interior detail, but the Airfix one is generally considered the 'most accurate'
Fujimi came along in about 1983 - engraved panel lines, but some question marks as to accuracy (and that thing about one wing being slightly further forward than the other).
Now, Boxes:
Airfix - always Airfix kit
Matchbox - Always Matchbox (AFAIK!)
AMT - Matchbox
Fujimi - always Fujimi
Revell - picture of model - Fujimi
- painting - probably Heller
Heller - Early style, black surround, Humbrol-Heller or Heller Orange style (photo of model) - Heller mould
- 'blue period' box (Painting) - looks like Airfix (as this style appeared in early 90s, could have been for a while!)