“Does that mean it is counterfeit?”
No. An authentication assessment that cannot reach a firm conclusion does not establish that an item is counterfeit. Nor does it confirm authenticity.
I would rather explain the limitation clearly than give a confident answer the evidence cannot sustain.
What remains uncertain?
A photograph may show much of an item clearly while leaving a relevant detail out of view. A comparison may depend on historical reference information for a production period that is not available. The explanation should identify the gap and why it matters.
A detail that cannot be seen clearly is not the same as a detail found to be inconsistent. Even a visible difference needs interpretation: brand, model, material, construction and production period all matter, alongside the relevant historical reference information.
Authentication considers the evidence as a whole. It is not simply a matter of counting features that appear consistent against those that raise questions, and a correct-looking serial number cannot settle the question.
Read the reasoning, not just the result
A useful professional assessment explains what evidence was available, what could be observed and what remains unresolved. That reasoning should be preserved so the conclusion can be reviewed.
The reader should be able to understand whether the difficulty lies in visibility, the available reference material or the interpretation of an observed feature. A clear explanation gives an unresolved assessment more meaning than a bare statement of doubt.
Would further evidence help?
Before arranging more photographs or further examination, ask: “Which unresolved question would this address?”
Clearer photographs may help with a visibility problem. Physical examination may be required where images cannot adequately answer the question. Neither guarantees a definite answer; further evidence is useful when it addresses the specific gap, not simply because there is more of it.
It is also worth asking what limitations might remain after that further work.
A buyer may choose not to proceed while authenticity remains unresolved. That is a decision about accepting uncertainty, not proof that the item is counterfeit. An owner should likewise avoid presenting an unresolved assessment as confirmation of authenticity.
If an assessment is shared, its limitations should travel with it. Removing them can change the meaning, even when the remaining words are quoted accurately.
The question to return to is straightforward: “What could not be established from the available evidence?” That is where any next step should begin.