If Ash caught a Johto Pokémon...
Since Ash caught a Gligar, it is likely it will evolve into Gliscor during the Sinnoh Journey. All Ash needs to do is find or receive a Razor Fang, train Gligar, then it'll evolve!
Since Ash caught a Gligar, it is likely it will evolve into Gliscor during the Sinnoh Journey. All Ash needs to do is find or receive a Razor Fang, train Gligar, then it'll evolve!