After several phone calls, I contacted the courthouse and reached a very nice woman in the Microfilm and Records department. She told me that yes they did have them but that no one from the department would be able to help me (understandable) and I would have to look for myself (preferable). She also told me that a genealogy group meet and researches in the LaPorte courthouse Vault on the first floor on Thursday mornings generally from 8:30 - 10:30 or 11:00. It would probably be helpful to go to the library and look through the indexed immigration records so that you would know what book, page, etc. that you should look in. Additionally, a genealogist is at the Michigan City library on Tuesdays usually from 1-5 and most often in the Indiana Room.
I plan to visit the LaPorte library early this next week and then go to the "vault" on Thurs. morning. Michigan City is in La Porte county and so all of the naturalization records should be at the courthouse in La Porte.
I hope this helps. I will post how well it goes for me.
BTW-All of the info listed on Dunelady was for abstracts, and I want the complete record and hopefully an image of the original.