Yes indeed ...
Ralle's decals are water-slide, but they won't stick unless the surface is smooth and semi-shiny. Same type as the ones hes sent me for the Rafale.
The procedure I followed is:
0) Clean the gelcoat surfaces thoroughly with isopropyl alcohol.
1) Apply the $3 spray can MM aluminum plate metalizer (2 coats)
2) buff to simulate aluminum panels
3) dust and clean to get rid of any residual aluminum powder
4) Apply two coats of sealer = Future acrylic, from home depot
5) Apply decals to what is now a nice smooth shiny surface
6) One more coat of Future to seal decals (not done yet)
I've learned about Future from reading FSM at Barnes & Nobles while my wife shops for clothes
... Kevin mentioned FSM some time ago as a good sunday reading for better scale finishes ...
The added weight due to the paint job is probably too small to measure on a digital scale - plastic model paints are extremely thin and light. The whole paint job for the Panther cost me about $6 in paints.
The original aluminum finish Panther had a lot of tiny rivets that would take a lot of work to duplicate
... I just used an artist silver pen.