I have to guess that the extreme tongue-in-cheek quality of the whole presentation played on the expectation that the Soviets would have access to this, themselves, before the meeting, and would find it very difficult to read between the lines and know what it was really saying.

More likely it was meant entirely for the Soviets' amusement/confusion, that they would have been obliged to pretend they had not seen, and some other doc still secret was actually read by (or to) the US crew.

Or, it is really just an inside joke that never had any larger meaning, and got assigned a document number more or less by mistake..