Yes, on built final event.
As far as i remember the commandpost is basically a func_constructible with thousands of stuff around, but important for the script is only the func_constructuble. You go in Radiant, set a scriptname to it and use that scriptname to reference it from script.
For example if you have scriptname ‘allied_commandpost’ on your func_constructible, then you would have this basic framework here to work with.
allied_commandpost
{
spawn
{
}
trigger setup
{
}
buildstart final
{
}
built final
{
//put commands here if it is built
}
decayed final
{
}
death
{
}
}
In built final you put your commands, such as indicate that it is built, set chargetimes etc.
Hope i remembered correct 