The brass is very unusual for a Tiger pilot on a Pro X.
Of Tiger's stock piloted shafts, the only one two I know of are 5/16X14 and 5/16X18, The 14 typical of Joss and Schon, the 18 would be Adam for example. On these, the pilot is made from phenolic, not brass. More than likely, it's one of these and I'm guessing 5/16 X 14 looking at the thickness of the thread.
In any case, nobody can tell what joint it is by looking at the insert. You could take it to the hardware store to see what sort of bolts fit it, or if you have a Schon or Joss around, if it fits these it will confirm it.