A little bit about fuel gauges....
devilspassion has already beaten me with his explanation about the gauge in the orange bug being in the speedo.
But heres a bit of info to share here:
The beetle got the fuel gauge as standard equipment in the year 1961. This means the 62 models got them. Before this the bugs had a fuel reserve tap on the front of the cabin near the pedals which could be flipped to use a quantity of fuel in case the level ran low.
This means the pre 62 models could only have fuel guages as accessory items!
Even after 62, the standard models continued to get the fuel reserve tap only. This continued right uptil 1972. Romanos white 1970 standard lacks a guage too and came with the reserve tap only.
From 1962 to 1967 the fuel gauges were mechanical units attached as a separate unit to the left of the speedo. An interesting exception we saw was the Made in Australia beetle rescued from Karachi which had the older style but electronic fuel gauge.
In 1968 a new electronic fuel gauge was incorporated into the mid of the speedo. This setup continued till the end of production.
The orange bug is a 1200 but not the most basic 1200A version. The giveaway is the rear view mirror which is of the detachable type seen on post 68 bugs. (This detaches if knocked hard....a safety feature in case of accidents).
Only the most basic 1200A models retained the old type pre 67 mirrors which were fixed on by three screws. Romanos Bug is again an example.
Im guessing that the orange bug in question came with a fuel gauge from factory. Its in the mid of the speedo. Of course there is a possibility that it was ordered with the car as an accessory (rather a neccessity!) or maybe the whole speedo was changed by a previous owner.
One interesting fact. VW speedos have the actual month and year of production stamped onto the back!! Its a bit hard to spot but its always there.