Is this the fuel filter(under car) for an 81 dl? I have looked all over the forums and all i can find is that its under the car by the tank. This little thing is on the driver side where the seat bottom would be, just in front of the rear tire and about 12 inches towards the middle away from the tire.

That doesn't look like the fuel filter, do you have the pump under the hood? If you have the pump under the hood then that's were the filter is, if the pump is under the car the filter will be next to the pump.

Pump is under the hood on the driver side right below the windshield. That little thing has two fuel lines from the tank going into it

I believe that is part of the return line to the tank, maybe some sort of evaporator thing.  The fuel filter should be before your pump in the engine bay.  I have removed all rusty lines (and things that look like that in your pic) and just run straight rubber hoses for return lines and had no problems.

That part is the anti flow rollover valve not feul fill fillter should be up front just after the feul pump

Yep the filter should be right next to the pump under the hood