The thing is, a real military coup was always successful. In 1997 they didn't even have to fight.
The military came together in a congress and presented a catalogue of requirements to secure the freedom of the country.
The president and his party had no chance to go against it.
The first thing you do in a coup is deprive the power of the state's head. From then on it's just a matter of time.
You don't walk into a city with a 2000 soldiers, 5 tanks and a helicopter, causing chaos and literally do nothing than just standing there at a friday evening.
You cut the head of the snake in the middle of the night, get in possession of the medias, shut everything down except your own broadcast, declare martial law.
Then you can show up with a huge military parade if necessary, just to show your strength and make it obvious you don't fuck around.
They did it several times before, they know how to run that show.
It was not a military coup, nontheless they used military units for it. This was either a stupid attempt to rebel against the state by a splintergroup or staged.