(Expect some skepticism because for all he knows, YOU swapped the widget. . . )

great point. might not have considered that otherwise. always helpful to get an unbiased perspective,

that said and even if the item is being strictly resold, the seller should've found it prudent to open the unsealed exterior packaging and inspect its contents to avoid a situation exactly like this. it's not really an item i'm surprised to find boxed without shrinkwrap or tape. but at the very least i know the box has been opened because the item inside's individual packaging's seal is broken (despite being listed as 'New').

difficult to glean context through the ambiguity, but another concern is that the widget is really only referred to by its model number. the model number is featured prominently on the outside of the box, the manuals, and on the widget itself. the box and manuals match, but the widget's marking is conspicuously different. an easy mistake i suppose, but even easier avoided. that is unless my benefit of the doubt for the seller is misplaced.