welcome to the team miyata world. I have an 84 and and 85
this link may be helpful
https://www.ragandbone.ca/PDFs/Miyat...%20Catalog.pdf
I think you need to decide what you want to do, restore it to as new spec or ride
restoring to as new is likely to be a quest as AX is not easy to find.
the handle bars are not original as an example
I personally would not worry about AX, get some dura ace hubs, etc from close to that period. edit original hubs were dura ace EX with early freehub and cassette
As orginally speced it came with tubular tires....I like tubies to that is how I would go really your choice