Don’t really know a thing about H.L. Greywack, the piano dealer with the stony name in Troy. But I do know that someone put a lot of effort into this ad from the Troy Northern Budget in 1885, because arranging all that lead was no small task.
Troy’s street numbering has remained fairly consistent through the years, so I think it’s pretty likely the piano store was located in one of the buildings that still stand on Broadway between Church Street and Fourth.