Recently, I've discovered the property records for Clinton County, New York on the LDS site. I had started to spot check certain volumes looking for records of Julius in the rough time frame that I understand he arrived in the United States / New York. Nothing turned up immediately.
Recently, I used my brain (I hadn't before) and scrolled ALL THE WAY through the offerings for those records and noticed the "Grantor - Grantee" indices. For non-real estate lawyers/professionals, what these are are indices of actually-recorded deeds that list who sold (grantor) and who bought (grantee) certain land. A LOT easier to search than the deed books themselves. These indices are the pre-computer method of creating a relational database of many records and information. In "modern" times, these computerize databases will be searchable and sortable by grantor, grantee, property identification, etc. But I digress.
The first record that I came upon was an 1844 transfer from Francis Hart to Julius La Porte. While Julius wasn't the first "La Porte" noted in the land transfer book (Francis Nelson or John / Jean Baptiste have earlier entries), Julius did appear before Julian. In fact, the first entry that I saw for Julian indicates that he bought from Julius, his younger brother. This transaction, I think, is further circumstantial evidence (although of very low relevance) that Julius and Julian were brothers. It would otherwise seem oddly coincidental that the among all of the other land owners in Mooers, New York, two men named La Porte would be transacting in land with one another. Possible, but it seems more than a coincidence.
I digress again. Below is the image of the recorded deed from Hart to La Porte. The penmanship is pretty good and its in English (though it undoubtedly had to be translated for Julius to understand), so I'm not going to transcribe it for now (later, I'll both transcribe and "translate" it from legalese to "real person English.")
In sum, Julius bought two acres land from Francis Hart which were originally part of a much, much, larger "refugee tract" (Lot 67 of 420) -- a giant tract of land that was legislatively given to certain refugees of Canada (from Quebec and Nova Scotia). I'm trying to track down exactly where it was in Mooers. It mentions a road from "Sheddeus Village to Plattsburgh" as one boundary line, but I cannot figure out where that is.
Here is the page of the deed recording - I think that Google will upload the entire image (which you can download to see in larger form) but if not, ping me and I'll send anyone interested a larger copy.