The F-104A and B models were the only ones that used the downward firing ejection seats. The F-104 was the second (F-106 was first) aircraft to be equiped with rocket assisted ejection seats. The A & B models were later modified with the rocket ejections seats.
The old style catapult ejection seats were not powerful enough to propel the seat past the stabilizer in a high speed ejection. Once the rocket seat was perfected, all front line aircraft were modified with rocket powered seats.
Now you know the rest of the story.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.