Yes I would also assume the Duckwiler and Dockweiler name have the same origins. I have seen this change in spelling every so often, even by German speaking pastors so it is not an unusauall spelling.
The origin of the Dockweilers in the Gedcom I posted are from Schleswig-Holstein. As far as I have seen to this time these Dockweilers are all direct descendents of Christian (1735 - 1810) who came to Schleswig in 1761 and had 13 living children at his death! Of course these children started to scatter in Schleswig-Holstein and Denmark. Then a number came to America but probably well after the 1770 date your ancestor first shows up in America.
So that probably leaves you with Christians place of origin in Eggenstein in Baden-Durlach after 1760 as an area to start your search. But,to date none of the researchers of the Schleswig Dockweilers have been able to gather much more information from this area and time period that I know of.
If you do a search of the LDS records you will find many Dockweiler records and the area of Germany they were from. The same with a current phone book especially in France you will find Dockweilers.
You probably will HAVE to find the town or village that Daniel came from before you can go back any futher. This information can come from ship passanger lists, naturalization record, obituaries (probably not in the late 1700s though).
There is one other possibility. Some books have been written in various areas of Germany recounting lists of people who immigrated from that area, whether to America or to other areas in Europe.