Thanks for all the suggestions. I figured going through the dealer would be a waste of time, since they would only turn around and contact Gibson anyway. I don't need to send in the guitar for repairs (that would be a whole different story). My issue is that the flubberguard pickguard I received with my 2018 Hummingbird was defective (curled up all over the place and wouldn't stay stuck, even after clamping it down for two weeks), and when I removed it to attempt regluing, it came apart and became ruined. So basically I need a replacement pickguard to be shipped to me (I guess at no cost since the guitar is brand new and under warranty - I registered the purchase and provided proof of purchase to Gibson by email as well).
One further comment: I am located overseas (Argentina) and local "dealers" (more like importers, really) have notoriously bad customer service. So I skipped the hassle and went direct to Gibson figuring it would be faster. In any case, I would expect Gibson to reply "you must go through your dealer", but I am surprised that I still got no reply at all. Perhaps the 4th of July holidays has something to do with it ... I wouldn't know.
Perhaps I am spoiled because I am in tech industry, and every company I work with has some kind of automatic CRM that replies and tracks every customer service issue. We do this ourselves at our company. Maybe I'm just not used to dealing with "old school" manufacturers?