A wild Wailord has appeared!?

I was pretty amazed by this guys. I'm replaying Pokémon Ruby and was surfing around Route 128 and 129 when a Wailord appeared. I was shocked because in the time I have played this game, I have never come across a Wailord like that. I decided to check a trusted site, but it only led me to ask more questions. I found out that there is a 1 percent chance of finding one while surfing. I thought I was pretty lucky until I saw the level cap. (Minimum level: 25 -- Maximum level: 30) I caught mine at level 39.