Which Credit Is Correct? Opening Credit or Closing Credit?

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To better explain the question, (Opening Credits and Closing Credits question)
As it begins, after writer, director, voices and other roles and proper names, the Opening Credits show Boston Quackie to be a Looney Tune and then as it concludes, the Closing Credits shows up, as if it a Merrie Melody cartoon. Daffy is not as wacky, like in 1948's "What Makes Daffy Duck". In 1957's Boston Quackie, Daffy & Porky are not rivals, Daffy is a secret agent in a spoof of TV series,(way back then) Boston Blackie.
Looney Tune is my first guess.
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PS: The director or producer may have picked Merry Melody, for the "instant girl", so the Slobovian leader needed an escort, and Daffy has a girl-friend that wants to get married/hitched, shortly after the cartoon begins.