Love in the Ring (German:Liebe im Ring) is a 1930 German sports film directed by Reinhold Schünzel and starring Max Schmeling, Renate Müller and Olga Tschechowa. Schmeling was a leading German boxer of the 1930s, and the film attempted to capitalise on this. Schmeling later appeared in another boxing-themed film in "Knockout" (1935).

Based on that paragraph can we conclude that this sentence is true?
These were the only two boxing films Max Schmeling ever appeared in
It's impossible to say