In R/B/Y it did. I remember its special stat, but I don't remember the level. I had a Charizard on my team and I faced Blaine. Before I beat him, it had a special of 158, but after I beat him it grew to 160. It didn't grow any levels during the time I fought him either because I remember trying to make sure it didn't fight any pokemon on his team JUST so I could test this. Though I didn't test it for the other badges, I'm SURE it worked for Blaine.
I know this doesn't apply in the 3rd Gen games though.