Timing belt replacement, are we lined up?

Hi everyone! The factory engine for our car is a 1998 Subaru Legacy Outback with a 2.5 liter engine (but, we found out that the engine was replaced with an unknown prior-year model in the distant past). So, we are now replacing the water pump and timing belt. This was done because it was almost 100,000 miles since the last, and the thing was making a funny noise. I want to know; is there any way we can find out exactly what year engine we have? And if I include these pictures can you guys tell us if we have the thing lined up correctly? Please talk to me as if I am a beginner, and pardon my naivete, as I am not experienced with this at all. Figured this car was a good one to practice on, being as it has 243,000 miles on it. But I do hope we can get it correct. Many Many thanks in advance!