It is really hard to beat a Recording!
1. Depending on the vintage of the horn, you know that the Special is a 2 piece bell (change in metal) but the Recording will be a 1 piece.
2. the full red brass (Re-O-Loy) bell will give a lovely warm tone.
3. Recording ... Recording ... etc
Check out
http://rouses.net/trumpet/olds66/trumpets.htm to see where they all fit!