Anders Knudsen / Ragnhild Olsdatter

I found Anders and Ragnhild in a 1865 census in Nesset with twin sons Knud and Ole age 4 years. 1875 census Nesset, Anders and Ragnhild with 5 children that we have discussed before on this forum, but there is no Knud or Ole. I am wondering if these 2 couples are the same people ? Also is there a way to track people leaving the USA and entering Norway in 1903 ?