Here's some info off the old Yahoo site that is relevant:
"I have read in various 'Buyer's Guide' articles that Pagoda VINs are stamped on the hood, trunk and doors. I have found the VIN on the hood (trailing edge, driver side on my car), but I have not found the VIN locations on the doors and trunk. Anyone have an idea where they are located?
According to Frank Mallory who has written a lot about the history of the 113, the number plate was not moved from the firewall to the door jamb until January, 1968. At first, the number plate was on the front of the door jamb. In August, 1970, the number plate was moved from the front of the door jamb to the rear of the door jamb.
Hans Strom: The number on the metal plate in the W113 engine compartment, near the hood catch is not the chassis number but something called body number "Aufbau No". It was used in the factory during assembly of your car. The last three digits of this body No were stamped into the hood, the cover over the soft top and the underside rear part of the hard top . You can also see it chaulked to the rear of parts like seats, door panels etc. This number is quite separate from the chassis no of the vehicle.
Regarding the Aufbaunummer stampings, Meredith (not always an accurate source) writes: "Factory-made aluminum alloy body panels, and the hard top, were all stamped with the body number or aufbaunummer." I was assuming that 'body panels' in this case included the doors and trunk as well the hood and soft top cover. Does anyone know if the Aufbaunummer is stamped on the doors or trunklid? In my car, there is a mechanical stamping of the last three digits of the Aufbaunummer directly on the underside of the hood at the trailing edge, to the left of the hood catch. I have not checked the hood cover as Hans suggests and the hardtop is safely stored, the better to enjoy the nice summer in Frankfurt. Seems like this is a pretty good test of originality for those panels where it is stamped.
Pete Lesler: here's another opinion: I have owned an early (Feb 1967) 250Sl since 1971. The vin plate on this car was loctated on the lower section of the A pillar just above the lower hinge attachment."