Who Are August Vandenberg's Parents?

My great-grand-aunt Louise DeValkeneer married a man named August Vandenberg in 1913. From what I have found, he was born in Belgium and moved to America as a small child. He married Louise in Pennsylvania, probably Allegheny county. I haven't been able to find their marriage license yet.
One thing we don't yet know is who his parents are. But I have a working theory.
In the 1900 census for Allegheny County we find a family of Vandenbergs, from Belgium, with a child named August, the right age of my guy. The parents are Campbell and Predan. There are 3 other siblings listed: Alice, Gusty, and Emma.
In 1910 we find the same family again. Parents are Campbell and Prudant, and the kids are August, Gustave, Emma and Leo. Alice would be old enough to be married by now, or she may have died.
Then in 1920 in Allegheny County we find August Vandenberg married to my relative Louise. We also see that just a few doors down from them is Gusti Vandenberg and his wife.
Could this be the same family? I think so. Hopefully I will soon be able to find the marriage record for Louise and August and hopefully it has his parents names on it. But for now I am just penciling them in, and will continue to look for evidence that Campbell and Prudant are my August's parents.