Looks like the bolt holes are there for Filter houseing. I am going to wash the motor off and I will try to post some better pictures after that. Truck has 85000 miles on it so I guess it didn't hurt anything.I would think most contamanants would end up in the bottom of the pan. Probably wouldn't hurt to add provisions for a filter anybody got an extra spin on set up? Definitely the first pressurized oiling system I have seen without a filter.
Dave