I was told that the only International License legally valid in Thailand is one issued in Thailand. There is a section at Jatujak for such licenses. If you have an International License issued outside Thailand, it needs to be endorsed and have the Thai language page inserted into it to make it valid. I could have checked today, but I was busy trying to get back to the office.

In an out in less than one hour, 105THB, and no Stat Dec required with a work permit.