I'm tempted to agree in principle. But I have some questions, as existentialism seems at odds with historical materialism. These questions aren't necessarily for you to answer, as each question would probably take a book or more to fully explore. But I'd be interested in yours and others' views.

1. a. What does objective meaning mean?
2. b. Is objective meaning the same as objective truth or objective knowledge?
3. c. Is objective meaning merely the result of scientific enquiry?
4. a. If Marxism is scientific, can it lead to objective meaning (without the need to say that this meaning came from a higher power or god)?
5. b. If historical materialism presents a 'totality', a grand narrative that claims to accommodate all truth, does historical materialism claim to know an objective truth?
6. If historical materialism does claim objective truth—or perhaps objective knowledge—does it also claim objective meaning?
7. If alienation is the separation of human subjectivity from objectivity, and communism is intended to end alienation by allowing a reunification of objectivity and subjectivity, does communism pressuppose that objective meaning is attainable, just not until it becomes objective-subjective meaning?
8. If communism does presuppose some concept of objective meaning, does this mean reality has (an/some kind of) objective meaning?
9. If the answer to 5 is, 'yes', does that mean any definition of 'objective meaning' cannot be universal? Perhaps it is historically contingent.
10. If there is no possiblity of a universal, ahistorical 'objective meaning' does that allow for non-historical materialists to lay claim to objective meaning in different eras?
11. If the answer to 7 is, 'yes', does that mean that religious claims of objective meaning could be objective (even if it came from humans rather than was bestowed by a higher power)?

I suppose this is why Marx told us to go beyond philosophy. We could go round in circles all day without improving the world one jot.