That you believe you can perceive a difference between these two experiences in no way indicates which of them must be "real", if any. What is it about your hallucinations that led you to dismiss them as mere hallucinations? What is it about "perceiving a ghostly event" that led you to accept it as genuine, and not, for example, just a different type of hallucination?
The first hallucination, I had unknowingly eaten a cookie with marijuana in it. I experienced the Ultimate Intelligence, and a couple of alternate life paths. In the hallucination, I was told/informed/understood that being "high" was the only way I could experience this. This was so I would write it off as an hallucination. And until recently I did. Being a hallucination does not necessarily mean that I was not given a glimpse of what the Ultimate Reality was.
The other hallucinations were seeing objects distort and lose shape and color. The analytical part of my mind still functioned well and I knew that what I thought I saw was not real.
Twice I have seen a person's face distort into something not very pleasant. The first time, I remarked about to the person I was with. They said that they experienced the same thing. While I know what I saw did not physically occur, it was an accurate portrayal of the "real" person. Again, I know that the perception is not what my eyes were seeing.
Another time I was with a person who was trying to point out spirits in a room. I could not see them. But I did see a "black mist" in the corner. The other person confirmed that they "saw" that also. I could also "feel" a cold curtain which formed a barrier keeping them in. It was like putting ones hand into a curtain of cold air (but a different feeling to cold). Very distinct boundaries. It was repeatable, and as "real" as putting ones hand into a bath of cold water.
As for what I was trying to get at: How do you reliably test the claims of others in these matters?
You have to ask a lot of questions, and get consistent answers without evasion. The frauds tend to double-down and exaggerate their story, or change the subject, or get really agitated.
And if you claimed to see a ghost when others claim to see nothing, what would be your conclusion? If you were to see a ghost with no other witnesses present, do you believe that makes your experience genuine by default? To what extents would you go to disprove your experience as genuine?
My conclusion is what I have always claimed. People are not seeing with their eyes. They are perceiving images in their mind. In the case above, there were a number of people who could see the same things over a period of years, at any time.
Where these images are coming from, and why, is the crux of the matter.