I had a G-Tube fore eight years. When they took mine out they told me it would close on it's own (really Doc? Come on.). So I placated them for two weeks. After the thing smelled like throw up for two weeks, my starbucks coffee came pouring out of me one day while I was drinking it. Needless to say, I was in that week to have it surgically closed.
I really think it depends on how long it's been in and how healed that site is for the G-Tube. If there is no fresh skin, it won't close on it's own.
I also want scar revision one day. Mine feeding tube one is the worst of all the scars I have!