I purchased a 14" twin rail the other day which seems to be almost entirely original and I'm trying to figure out when it was made.
Some points of interest that might help with dating or just be for the sake of interest.
It looks to be Alpine Green with black side cover and handlebar plate. It's got a brass dual name badge (model 450407) which in itself is interesting because another 14" frame i had with the same model number was also dual plate but was not brass. It's got a cast iron clutch. Confirmed with a magnet but i didn't need to anyway because at some point in it's life it suffered some sort of injury near the cotter pin and has been brazed. Speaking of cotter pins, it has a single cotter pin only. No secondary grub screw (unlike the aluminium clutch on my 14" daily driver). It's running a Kirby Tecumseh HK25 (And it is running, although it wasn't when i got it). The cutting reel bearings were the old style bearings that were open on one side.
Humorously the lever on the handlebars is held in place with a 1/4" bolt and two nuts. Pretty sure that's not factory.
So with all of this info and things I've gleaned from these forums it's looking like this mower might be about 1975-76.
