Normally, with mechanical fuel pumps, there is a sock filter on the end of the fuel pickup in the fuel tank to catch big stuff, and the replaceable inline filter goes between the pump and carb. Sometimes the filter is in a chamber on the pump and looks like part of the pump.
While there are exceptions to every rule, most fuel filters are designed to have fuel flow from the outside-in, like an air filter. If you can see inside (clear type) then you can see how it would flow. If it's a metal body type, it should either be marked, have a larger or threaded inlet than outlet, or is bi-directional.
Personally I prefer the filter before the pump, especially on older cars where the in-tank sock may be damaged or missing. This keeps crud from the pump. I also use a clear filter to see if there is fuel in the line and if it's clean or not.
One potential problem with the filter before the pump is that you are pulling fuel thru it and the negative pressure could potentially pull air into the system.