Are you being serious?
The evidence for this device being an astronomical computational instrument places computational code within its mechanical components.
If we were provided the engineering specs, a number of us could write the program embedded in those gears.
“Computer” is semantics. In the era in which it is believed to have been assembled, it is the equivalent of a Cray 1 existing in 1940, before Colossus came about.
It is truly a computer, the irony being that even today it is beyond most people’s comprehension.
The Antikythera mechanism is very impressive, actually stunning for the time period. Yet, it is not a "Von Neumann Engine". It cannot be compared to a modern computer; and, it is not a computer in the sense used today. I have been working with computers since 1967. I have been reading and studying the field all of the intervening time. I have made my living in the field; and, I'm an "embedded guy" who skirts the line between computers, mechanical devices, and scientific instruments
Archeologists are not qualified to arbitrarily classify the Antikythera mechanism as a computer.
Calculator: a device that performs arithmetic operations on numbers. The simplest calculators can do only addition, subtraction, multiplication, and division. More sophisticated calculators can handle exponential operations, roots, logarithms, trigonometric functions, and hyperbolic functions.
Computer: a programmable electronic device that accepts raw data as input and processes it with a set of instructions (a program) to produce the result as output. It renders output just after performing mathematical and logical operations and can save the output for future use.
The difference, and a very important one, is that a computer is "programmable". This is where I am making my distinction.