It will be Full Pressure, but not Full Flow Filtration. That was on 261 only (2 ton and larger). The filter could have been factory, but most liley was a dealer installed ad-on, especially if it is a Fram instead of AC.
From what I can tell, it sounds like you may have a rod bearing going sour. I would pul the pan and inspect the rods for exsessive play. A teardown might be in order, especially if the crank is damaged.
