I've never owned a Bug with a thermostat and control flaps still intact and working. My 1300, and my girl's 1302 are missing theirs.
Our climate in southeastern US is between 0 and 35c anually, and doesn't make a thermostat very nessasary. I usually take about three minutes to warm up before driving anyway.
I don't often drive either of the Beetles when it's below 5c.
My little Chevy truck got a much better heater
In your part of the world, I to would consider it a nessasary component to achieve operating temp quickly, improve fuel efficiency, and reduce premature engine wear.
Late-ro
Yetibone