On the 1970 and 1971 cars the emission control plate (black finish on aluminum plate) was riveted to the left hand front wheel arch. On the later cars an adhesive silver label with black print was used at the same location. These labels included both the emission control statements and engine settings with each year getting a plate or label specific to that model year car. The 1969 cars were treated more like the TR250 with two stickers, one with the emissions statement, the other with the engine settings, both applied to the underside of the bonnet. The Commission Number Plate was riveted to the left hand front wheel arch for both the 1969 TR6 and the TR250.
While there is some information out there that indicates that the Commission Number Plate (aka VIN plate) on 1970, 1971 and 1972 cars was located on that left hand front wheel arch as well, I know that is not necessarily the case. I believe that for the cars intended for outside of the US market (possibly all of the NA market), it would be correct to say that the Commission Number Plate was riveted to that wheel arch for those cars. In the US (and again possibly all of the NA market), that space was taken up by the emissions control plate and the Commission Number Plate was relocated to the left hand door jamb like on the later TR6s for all markets. I've yet to see a US spec 1970, 1971 or 1972 TR6 that did not have the Commission Number Plate on the left hand door jamb.