This question is over a year old, but maybe I can add something to it that will help others in their research (sorry if that information is already known): Rheinland-Pfalz belonged to Bayern (Bavaria) from about 1816 to 1946.
Due to the bad economical situation, many Palatinate people emigrated to (mainly) North America up until the second half of the 19th Century. (As you might already know, that included the Heinz (ketchup) family and Trump's ancestors - they were not only from the same village, but also distantly related.)
Source:
https://de.wikipedia.org/wiki/Pfalz_(Region)#Bayerische_Zeit
This might be helpful to know when looking for documents, as they might be "hidden" in Bavarian archives, where one would not immediately think to look.