Thank you so much for replying to my message.
Some counties within the state of Wisconsin do have records that can be searched by the county reference librarian for little or no fee. However, that avenue became a dead end for me. So I'm left with not exactly knowing where the ancestor got his papers from (if it was even in the state of Wisconsin), let alone trying to figure out his arrival/destination information for ship passenger lists. Quite a problem!
Interesting notation about the county clerk possibly keeping immigration/naturalization records. I believe that the county clerk doesn't within the state of Wisconsin, but I'll check to make sure.
If you can think of any more possibilities to finding the immigration/naturalization records, I would appreciate your input!
PS. I have ordered a passenger list based off of a search of the Germans to America index. I have my fingers crossed that it is the one and the same ancestor.