Sorry to say, but the carnet regulation require the carnet to be stamped out by the local customs when your vehicle arrives in that country where the carnet was handed out. At least that's what they told me here in Munich after returning from Oz. So I had to wait another month until the bike arrived :-(
I'd give it a try if the carnet has been stamped out at Bangkok, but most probably you won't be any luckier than I was...
Only when we pause to wonder
do we go beyond the limits of our little lives.