Uninformed font speculation

I came across an interesting 1874 font choice. Exterminator B. Pickman Mann* printed up letterhead outlining, in a few paragraphs, his services. Name in large, fancy gothic above, block caps in the unadorned serif font of the body. (I should become a font geek, then I’d be able to describe it more accurately.) But the office address and hours are in a larger, bolded, sans serif. Is that just intended to call attention to the relevant information? Is the dissonance just a matter of my offended design sensibilities? It is reminiscent of fields pulled from elsewhere, which now don’t need to be differentiated but sometimes still are (because that somehow makes it seem like a personal form letter?)…so was it perhaps the same thing? The paragraph text is pretty specific to Mann’s business, so I have a tough time imagining anyone else using the template. Maybe he did, or planned to in case he ever moved his office? Perhaps investigation into 1870s printing technology would shed some light (or at least eliminate possible explanations).

* Did he have a model? A gigantic creepy cockroach of dubious geometry, perhaps?