The best way to know for sure is to just open it up and have a look
Measure bore and stroke, check for part numbers.
That way you can also tell the condition of it.
If you want to save the head gasket, you can measure the stroke via the spark plug hole. And estimate the bore with a bore scope if you can find one? But the stroke probably tells most of the story.
Or just open it up and have a proper look Why not?