In April of 2003 I bought a box of second-hand Lego that contained a large number of (almost) complete
late 60's and 70's sets: two big trucks
(331
and
337),
seven Legoland 'miniwheel' vehicles and one building
(346, very nice).
One of the vehicles is the double tanker truck,
644, from 1971. But when I built it from the
scans on Brickshelf,
I noticed something strange: the number of wheels is not consistent on images of this set. The instructions and a Danish ad show 4 wheel bricks,
but several other sources suggest that there should be 5...