Not necessarily. Theoretically, one could have very specific knowledge of Chinese, possibly acquired from very limited but deep experience. Imagine one person who has spoken Chinese only at the harbor, and has complete and total mastery of the maritime vocabulary of Chinese but would lack all but the simplest verbs relevant to the conversations happening just a mile further inland. Conceivably, a series of experts in a very localized domain could separately contribute their understanding, perhaps governed by a person who understands (in English) every conceivable key to the GLUT, but does not understand the values which must be placed in it.

Then, imagine someone whose entire knowledge of Chinese is the translation of the phrase: "Does my reply make sense in the context of this conversation?" This person takes an arbitrary amount of time, randomly combining phonemes and carrying out every conceivable conversation with an unlimited supply of Chinese speakers. (This is substantially more realistic if there are many people working in a field with fewer potential combinations than language). Through perhaps the least efficient trial and error possible, they learn to carry on a conversation by rote, keeping only those conversational threads which, through pure chance, make sense throughout the entire dialogue.

In neither of these human experts do we find a real understanding of Chinese. It could be said that the understandings of the domain experts combine to form one great understanding, but the inefficient trial-and-error GLUT manufacturers certainly do not have any understanding, merely memory.