It has rear openings as well with plugs. In fact that's probably what they want you to strictly use. I just had noticed it has a 1" opening at the bottom as well and this way would be a cleaner install. I'm sure I could cut the opening larger I just don't have the post in my hand yet to take a look. Also it's painted and galvanized. Obviously once you start cutting you damage that coating. Sure I can touch it up with paint afterword and it's underneath and it visible. Just probably won't be quite as corrosion resistant but I'm sure it would be fine.