Paul,
It is already clear coated. You must clear coat. Model Master is not fuel proof. I used Minwax Polycrylic Semi Gloss in this case. Using Gloss is way too shiny. It is a water based polyurethane. It is not raw fuel proof. If you spill raw gasoline on it, wipe it off immediately. On my next project I will use automotive two part clear coat. However this is alot more expensive. I like using Model master because it covers very well with an airbrush. You will not use alot of heavy paint. I painted the entire 1/5 scale plane using 12, 1/2 oz bottles of Chrome Silver Enamel. That is 6 oz of paint. After the thinner evaporates, you have maybe 2 oz of paint left on the plane. Then add graphics and clear coat maybe total paint weight of 8 oz.

My two choices for paint are latex house paint and model master. Finding the right paint to do the aluminum finish was tough. I tried

1) Model master, Acrylic aluminum, Color and look, not even close to aluminum. clear coat does not stick well.
2) Model master, enamel aluminum, Color and look, not close to aluminum. too grey. However, the rudder on my "Angels Playmate" is painted with enamel aluminum. Real plane has aluminum painted cloth rudder.
3) Model master, Buffing and Non Buffing Metalizer. Color is awesome. Could not get anything to stick to it however. Very fragile. If you put any tape on it to put graphics on you will leave tape marks and the tape WILL pull the paint up.
4) Alclad paint, same result as metalizer.
5) Flite metal stick on aluminum sheets. Can't beat real aluminum. Problem that I found and did not like is that the finish is soft. You will leave marks on the plane from stuff the model touches. You can put a fingernail mark in the aluminum way too easy. (I fly my models, No hanger queens here.)
6) Model master, enamel Chrome Silver, Too shiny if not buffed but looks pretty good when buffed with steel wool. I did have adhesion issues, and tape marks, but not as bad as with metalizer.

The problem that I encountered with the metal colored paints did not happen with normal colors. I think that the problem is due to the metal powder used for the pigment.

Karl