Yes, it does matter. First, how many lines does your fuel tank have? Two or three?

Let's start with a two line setup. Two lines come out of the tank, one is a vent, which goes to your muffler for pressurization of the fuels tank. The vent line must have access to an air pocket in the tank when the tank is full. Usually the tube that the vent is attached to have a slight bend up, away from the fuel. The second line is the feed line to your carburetor. Attached to the other side of that line is the "clunk." The clunk is a metal nipple that is suspended from another piece of fuel line inside the tank. It is supposed to barely reach the back, bottom portion of the tank so that it can draw out all the fuel. If it is too long it can become lodged within itself and reduce your flight times, or starve your engine of fuel at a very inopportune time.

Three line system. This setup has all the basic components as a two line system except that it has a third line that is generally used for fueling and defueling the tank. I use this setup on my .25size Modeltech Extra 300. The third line has no clunk. It has a piece of metal tubing that the just clears the stopper. This allows me to fuel and defuel without removing the tubes from the muffler or carburetor and makes life with a cowl around the engine much nicer. There is however a stopper in the outboard length of tube to prevent the fuel from flowing out.

Hope this helps.