If that was the first range trip, NOT BAD! Heine sights can be a pain, but trigger control can also cause the low and left function too.
Yes you can loosen the rear sight and tap it in the correct location, of course they use lock tite, so heat from a hair dryer, or heat gun (carefully applied) will help with the loosening. Some say the key for the security lock is the correct size for the rear sight, but I did not have to loosen mine.
My PT111 came with a manual, but you can download one off the Taurus web site.