Re: [WIP] Trumpeter 1/35 USMC LAV-AT "Operation Desert Storm"
For me, it depends on how many decals there are. If it is just a couple of bumper codes and maybe a vehicle name (I could dig mine out and look but too lazy!), I would just brush on some future in the spots that the decals are going to go on, slightly bigger than the decal, let dry, and decal as normal. Once the decals are dry, then future the whole thing and then move on to the washes.
As as rule, I will put a flat coat after the washes, and then do any dry brushing or paint chipping, and then pigments. I generally don't flat coat after pigments, but that is me. I don't like the effect that a matt coat has on the pigments. You get the kit looking good with dirt and dust, go do a matt coat, and it makes your weathering disappear. What I will do however, is a final dust coat of highly thinned out buff or deck tan (sometimes both) to give it the final light dusty look, with will also give you a final matt look because of the matt paint.