Well, these are aftermarket catalogs from a company called RevolutionParts, which manages a lot of auto manufacturers' catalogs.
I think it is updated, when they receive notification that a part is unavailable. But it is very very inconsistent and can lag the actual NLA date even by years.
For something like this transmission tunnel blanket, which probably does not have very much demand, they probably never received notification that it's NLA, because nobody ordered one.
You should bookmark this site on your browser -- it is the best site there is (MB Classic Parts) to determine whether a part is available or not, and is usually updated by MB within 1-5 days after the actual NLA status of a given part:
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To search for a part, put an "A" in front of the part number, and no spaces in the part number.