I think you misunderstood what I meant. I wasn't implying that the Sega Master System version was the first, and no other version came out before 1987, I meant that the Sega version came out in 1987, and the Sega Master System came out in 1986. It's the same game as the Commodore 64 version, but with better graphics and an extra level added. So by this logic, it would have made sense that if an Amiga version had come out, even though it may have been years after the original C64 version, it could have still sold well, and I'm sure it would.
I'm sorry you went to so much effort to prove something we already knew and took for granted. No one is arguing that the 1984 C64 version wasn't first.
When I said "original" I just meant it was based on the original Ghostbusters game, not Ghostbusters 2 or The Real Ghostbusters.