Both these buildings are quite utilitarian, with ground-floor storefronts and upper-floor workshops; but each is adorned with its own distinctive classical detailing. The Greek-key pattern shows up on both, but no. 819 in particular adds a profusion of other ornaments that distinguish it from its neighbors.
Once again, the narrowness of Penn Avenue makes it difficult to get a complete picture of the façades of these buildings, so the tops are a little blurry.