Yes, it's entirely possible to know what something means without knowing its worth. In fact, the "meaning" and "worth" of something are often subjective and context-dependent, and may be evaluated differently by different people.
For instance, consider a painting. You may understand what it is (a piece of visual art), what it represents (its subject matter, symbolism, or the emotions it evokes), and even who made it (the artist), all without knowing its monetary value. The "worth" of the painting, in a financial sense, would be determined by various factors such as the reputation of the artist, the demand for their work, the condition of the piece, etc. This is something you might not know without an appraisal.
Furthermore, the "worth" of something can also be sentimental or personal, and not necessarily related to a monetary value. A handwritten letter from a loved one might have little to no financial value, but to the person who received it, the letter might be priceless.
Thus, understanding the "meaning" of something often involves comprehending its nature, purpose, or significance, while knowing its "worth" involves recognizing its value, which can be evaluated in monetary terms, but also in terms of usefulness, importance, or emotional significance. The two are not always connected, and knowing one doesn't necessarily mean you know the other.