The law simply states unloaded. According to the RCW's;
(9) "Loaded" means:
(a) There is a cartridge in the chamber of the firearm;
(b) Cartridges are in a clip that is locked in place in the firearm;
(c) There is a cartridge in the cylinder of the firearm, if the firearm is a revolver;
(d) There is a cartridge in the tube or magazine that is inserted in the action; or
(e) There is a ball in the barrel and the firearm is capped or primed if the firearm is a muzzle loader.
You should be able to carry the magazine in your pocket and be OK.