Wally Campo was probably born in 1923, not 1921. In a 1943 article from the College of the Pacific, a thespian named "Wally Campodonico" gets a fleeting mention. Given that the book "The Story of American International Pictures" gives Campo as majoring in drama there, it seems likely that's him. There's a "Wallace J. Campodonico" in the CA birth records born on April 23, 1923 in Alameda County, and per public records, he resides today as a 99-year-old in Valley Village/North Hollywood in LA.
The IMDB date appears to have been plucked from a guy named "Walter Campo" who can indeed be found with that DOB in the CA birth records, but the college mention of "Campodonico" make it highly unlikely the actor was born with that last name, and I don't see any records for a Walter Campo who appears to live today.