No.
Rhydon, in Pokemon FR/LG, does not evolve.
..........level rhyhorn to 42.....get a rhyhorn from safari and evolve it to rhydon
Rhydon at Lv 42.
Rhydon will not evolve in leafgreen or firered you have to migrate it to diamond, pearl or platinum then trade it to evolve it.
You can catch one in the Safari Zone and Cerulean Cave.
In indigo, you don't need hold items to evolve them through trade. Just trade a Rhydon. Your welcome :P
Rhydon doesn't evolve by level. When the Protector is attached to Rhydon, trade it and it will evolve to Rhyperior.
Rhydon evolves into... RHYPERIOR!!
Rhydon evolves into, ---------{rypherior}
Rhyhorn evolves into Rhydon at Level 42. Rhydon can then evolve by attaching a Protector to it and then trading it.
Rhydon is not able to evolve in FireRed.
In Pokémon FireRed, you can obtain Rhydon by evolving Rhyhorn. Rhyhorn can be found in the Safari Zone, specifically in the areas where you can encounter wild Pokémon. To evolve Rhyhorn into Rhydon, you need to level it up to level 42. Additionally, you can trade with Pokémon LeafGreen to get Rhydon directly, as it is exclusive to that version.