By experience, I do not imply a subjective experience like that of an animal (with memory, decision making etc).
Could a rock, for instance, have individuated experience of its existence like a bacteria, fungus, or an RNA virus does.
No, by the definition of experience, rocks do not experience their existsence.
To be clear, sometimes people see 'experience' as a synonym for 'history', which is likely a result of 'experience' being used metaphorically for 'history'. For example, "what did that boat experience at sea? She looks sad!" This is a form of anthropomorphism, and as such is not literal, but poetic. If you believe in spacetime, all things have a history. But literally experience is generally understood as distinct from history such that all things have a history, but only some of them experience it. To wit:
Practical contact with and observation of facts or events. "he had already learned his lesson by painful experience"
Note that the plain language definition includes terms like observation, facts, and events, all of which are related to the epistemological source of knowledge known as introspection or for some consciousness. Whether you lean to rationalism or empiricism, the SEP entry 'consciousness' recognizes there are some widely recognized theories of consciousness:
9.1 Higher-order theories
9.2 Reflexive theories
9.3 Representationalist theories
9.4 Narrative Interpretative Theories
9.5 Cognitive Theories
9.6 Information Integration Theory
9.7 Neural Theories
9.8 Quantum theories
9.9 Non-physical theories
Between the advent of science and particularly psychology, in the West, experience is seen as a peculiarity of certain types of systems historically described along the mind-body duality. As such, the answer is no.