Iím not sure exactly when the tall flattop fenders came out but they are usually on the 40hp and up tractors. They usually have the headlights in the top front of the fenders.
I bought a Ford 2310 last year that has the tall flattop fenders with the lights in them. I wasnít sure if I would like them to start with but the more I used the tractor the better I like them. They seem to offer a little more protection to the operator than the standard clamshell type and they have a grab handle at the front to grab a hold of when mounting the tractor.
You might try one of the parts companies listed on this forum or your local tractor dealership. You might also run a wanted add in this or other tractor related sites. HTH. Rick H. Ga.