The serial number identifies it as the fifth iteration of the first f/2.8 Q version, non multi-coated, and appears to have been factory modified with the Ai kit 44.
You don’t see many Nikon plastic bubbles these days, especially in this condition.
A better test for sharpness would be to use a tripod, or flash. You did well for $65.
The lens has been modified as AI but according to my records the serial number belongs to the very first model that remained in production from 1965-1974.