LEGO has had a long-standing relationship with Shell Oil and has produced many sets that feature the company’s logo and brand name. As Shell has updated its logo, LEGO sets have followed. There are some variants of the logo that are not cataloged in Bricklink, however. If you are completing or replacing parts from an old set, you may want to check with your seller to be sure you are buying a part that matches the others in the set.
The first LEGO sets with the Shell logo were released in 1966. At this time the Shell logo was a stylized scallop shell in yellow on a red background, with the word SHELL in block letters. This is the version of the logo found on the 1×2 brick 3004pb011 from four sets released in 1966 through 1972. The 1×2 brick with this logo version was only released in red. There are Bricklink sellers who have the piece listed in other colors such as white and yellow. These are probably listed in error – the pieces they are selling are different versions of the logo.
Confusingly, Bricklink calls the earliest version “Logo II.” What is sometimes called “Logo I” is the version that Shell adopted in 1971, and which first appeared in LEGO sets in 1973. This version is a more stylized shell without the lettering, printed in yellow with a red outline.
There are two distinct versions of this later logo as they appear on LEGO pieces, and on the printed 1×2 brick in particular. The earlier version is slightly larger, has longer red “rays” and is printed in thick, solid colors. The later version has shorter red rays that form a semi-circle at the tips. The colors are not usually as solid, and may show the pattern of the printing pad used to apply the ink.
The earlier version appeared in sets beginning in 1973 and was used at least through 1977. In 1978 the later version first appeared in sets, concurrent with the first Shell-branded minifigs, which had the simpler later version. Stickered parts from the 1980s on use the later version.
LEGO frequently used up existing stock pieces after new versions were introduced, so these dates are approximate for sets that were released near the transition points. The important thing to know is that Bricklink does not distinguish the early- and late-1970s versions in its catalog. When completing a set, be sure to check to see you are getting the appropriate version.