It looks like a standard domestic carbureted engine fuel filter. Keep in mind that most carbureted engines run on around 7psi fuel pressure. In addition the small filter is not meant to filter the huge volume of fuel pumped through the W113 fuel injection system. An in-line filter after the electric fuel pump in not original but can work, but you need to upgrade to a good quality in line filter which can handle the pressure and volume. There are lot of choices out there. Most later MB fuel injection cars had an inline fuel canister/filter after the electric fuel pump. They are large and robust and can handle fuel pressures over 100 psi.
Some other less pricey domestic in-line filters can work, but make sure it is for a fuel injected application witch is designed for higher pressure and volume. Might be easier to go back to original and all the guess work is taken care of.