Help with 3rd member casting number

['65Burb]

I did a bunch of searching and I think that the 12 bolt under my '65 is original. Therefore, just asking those here who are infinitely smarter than me to let me know what they think. Casting number on the 3rd member looks like 3858625 with an N above that number. Sequentially, does the "385....." look like it is correct for '65?

I need to swap the rear axles to get to 5 lug and I want to be reasonably sure that I will order the correct kit. Responses greatly appreciated.