matte finishes have a higher surface area then high gloss finishes. matte has micro ridges and valleys, this is how they diffuse light and cause the matte appearance. these ridges and valleys give moisture somewhere to stick to and also impede evaporation. the micro ridges and valleys also create a larger surface area allowing for more possible steel to be exposed to ambient sources of oxygen. high gloss finishes are flat in comparrison and dont experiance the above effects as greatly.
foam lined gun cases create a closed, sometimes saturated enviroment. this can be a breeding ground for rust IF the air is saturated with common water condensation. there are several industrial products on the market which will displace water from saturating air by instead saturating it with oil. the most notable of these products is ZE-rust from flambeau. products like this are designed to cause a oil condensation within the closed enviroment preventing rust but evaporation of water is greatly slowed in the given enviroment.
raising the tempature within your gun cabinet will greatly improve evaporation but it will also super charge any existing rust. just remember that rust is simply iron oxide (type 1) and increasing the tempature will speed up the oxidizing much in the same way acids are supercharged when heated. of course this wont be a problem if the evaporated water has somewhere to go like silica gel or just by opening the cabinet every now and then to allow the water saturated air to escape.
in general the kiss principle will prevail. drying the gun then wiping it down with a good oil should be sufficient.