I'm researching paint guns and came across the DeVilbiss 802342 kit. I noticed though that it has 1/4" NPS threads, even though I've only ever seen NPT used for air plugs. A quick search indicates that these types of threads will engage, but won't seal properly. No sources seem to say whether or not this can be fixed with thread tape/dope, only that thread tape/dope is required for NPT connections. One other source I found said that generally NPT is used for air connections and NPS for fluid connections, although the DeVilbiss website specifies that this is for the air connection.
Looking at various websites, I can't find a 1/4" NPS air plug anywhere, even McMaster-Carr. I've never paid much attention to the fittings on my air tools, just checked whether they were male or female threaded and put a 1/4" NPT plug on there. Is it common for air tools to have NPS threads on the tools themselves? Will a NPT plug work with NPS threads (assuming proper thread sealant is used)?