>(the Falcon 9 also is the second iteration of the Falcon rockets, not the ninth, so…)
Falcon 9 has nine first stage engines, Falcon 1 had a single engine. It's not a version number.
Edit: I had to look it up because Saturn 1 is not a single engine vehicle. It turns out that the Saturn V is design C-5 of the Saturn family of rockets, with A, B and C1-4 designs preceding it (not all designs where built), so the "V" in Saturn V is basically a version number, despite the Saturn V first stage having 5 engines
Falcon 9 has nine first stage engines, Falcon 1 had a single engine. It's not a version number.
Edit: I had to look it up because Saturn 1 is not a single engine vehicle. It turns out that the Saturn V is design C-5 of the Saturn family of rockets, with A, B and C1-4 designs preceding it (not all designs where built), so the "V" in Saturn V is basically a version number, despite the Saturn V first stage having 5 engines