There is a Milwaukee Braves baseball pennant on the wall of Merrill's son's room. This film takes place in 1951 and 1952. The Braves didn't move to Milwaukee from Boston until 1953.
Darryl Zanuck is seen watching dailies from the filming of "Gentlemen Prefer Blonds", which was filmed and released in 1953, even though the final scenes of "Guilty By Suspicion" take place in February, 1952.
Before going to London, Joe is seen editing the classic "The Boy with the Green Hair", but that movie was already released in 1948 and "Guilty by Suspicion" takes place in the early 1950s.
Dorothy Nolan's car, a 1941 Chevrolet, is supposedly equipped with Powerglide automatic transmission. Powerglide was not offered on Chevrolets until 1950.
When David Merrill meets with Felix Graff in the flophouse hotel, Graff pours himself a shot of Maker's Mark Bourbon which didn't exist as a brand until 1958.