Along with the set number, my old LEGO instruction booklets have a larger number in a smaller font on them as well. What do these numbers represent? What are they for? Unit/serial number?
This booklet for example: Lego set 8034 cover, with 120733 It has "120733" written on the right in the black border at the bottom, in a font about half as high as said border. You need to zoom in to see it.
My newer sets' instructions don't seem to have this.

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    I'm not sure if this has any relevance, but Brick Owl use this number as the Item No. for instructions. see 8034 Sep 2, 2022 at 2:03

1 Answer 1


Such identifications exist not just on building instructions but on other printed items like catalogs, brochures, leaflets and so on. I don't have anything to base my answer on, but my guess this is some sort of "inventory ID". Just to make things easier to store and refer to instead of using using full name like "Building instructions for 8034".

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    And instructions could have been different for different regions (A4 vs. Letter, for instance),
    – RSchulz
    Sep 2, 2022 at 13:50
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    I agree. Having an article number or ID number for printed materials is a very common business practice. It allows you to treat the materials just like any other item for warehousing/shipping/manufacturing purposes. When you look at recent Lego packing boxes you see next to the barcode a line "Item: XXXXXX"with a 6 or 7 digit number. This probably serves the same purpose for the box itself.
    – Tonny
    Sep 2, 2022 at 14:01

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