Adrian

I called somebody who would know. These stickers were not installed officially at the factory. They was another who person informed me that this was USA DOT anti-theft requirement.
There may have been some form of partnership between the production line and the PCNA to get these stickers installed in certain places. I cannot deny this possibility but these stickers are not a standard VIN identification system. I have also been informed that some VWs also had these stickers but the requirement has since been dropped. Based on the number or types of 964 that seem to have these stickers it may be limited to very few models.
It maybe a useful tool to look for accident repairs but seeing as there is no standard or even any idea of what models have and do not have them somebody will have to go out and get all the facts. I suspect quite honestly that is may well be a pure Turbo 3.6 issue in the Porsche world. Maybe it is just a Turbo powered car issue over a short time.
Ciao,
Adrian
964C4

J-McDonald

It may be a US anti-theft requirement. All late model Mercedes Benz cars have the VIN number inscribed on all the major body panels (fenders, doors, trunk, hood). The guy at the local MB dealer said that they check all cars they're considering taking back on trade to see if they numbers on the body panels match.