What legal guidelines exist for completeness of a Materials Safety Data Sheet?
OSHA's FAQ says that chemicals that make up less than 1% (0.1% if it is a carcinogen) of a product do not need to be listed on the MSDS. So it looks like 3M could be in compliance if the oderants are present in trace amounts (in that case, I have no idea why they feel the need to include the thyme oil).

The only relevant thing OSHA seems to say about consumer products specifically is that employers are not required to provide an MSDS for consumer products used in the workplace, as long as the consumer product is used in the same manner as a consumer would.

The Consumer Product Safety Commission specifically disclaims jurisdiction over chemical products, and the Chemical Safety Board doesn't appear to have anything related to consumer chemical products.