Is it okay to republish an uncopylocked Roblox game?

Before you publish, open every script in it. Uncopylocked places and free models are one of the main ways backdoors get passed around, a require() with a long number or a chunk of obfuscated code buried inside a model can let someone else run commands in your game. Search the explorer for scripts and actually read them, it doesn't take long.

Uncopylocked on purpose means they're fine with it. Credit them anyway. The real risk is assets inside it that belong to someone else, so replace anything neither of you made.