It’s generally a good idea to clean a new gun thoroughly and apply some sort of protectant. Doing a basic field strip will help make you familiar with the firearm, and you get rid of any debris that may be left from production (I find this more on less expensive guns). The factory will sometimes apply a shipping oil or grease of some sort that can eventually gunk up your firearm with use, best to get rid of it and start out with a quality lubricant.

The Stack on cabinets aren’t air tight, but a dehumidifier or desiccant will help. You can get by with frequent inspection of your firearms and reapplying whatever product you’re using as rust prevention occasionally.