More likely, I suspect that they were always from Würzburg and Adelberg, and at immigration it got changed to "Wirtzburg" and "Alderberg". Or, Alderberg could have been Oldenburg, in Niedersachsen. US immigration officials didn't know much about German geography or spelling.
If you are near a Family History Center, you might go there and look at emigration records from Württemberg. I think Adelberg was in Württemberg, and there was documentation of emigration from Württemberg at that time. The Family History Center has microfilned copies those records. That's how I found some of my relatives that came from Württemberg.
Check your local library's genealogy section. Some Mormon genealogists, who could read the old Sütterlin handwriting, assembled those microfilmed emigration records and compiled them in a series of books called, "Emigration from Württemberg". Some libraries (e.g. Denver) have those books.