This has only been true since 1986. Before then, copyright had to be stated, which is why the copyright symbol was such an important indicator. One could also register a copyright to get more protections.
The Library of Congress provides a search engine for registered copyrights. They also do paid searches, since the search engine is not perfect or the friendliest. They’re a good resource.
BTW, ASCAP was the mainstream licensing organization back in the day. Downscale genres of music, like country, were more likely to use BMI. There were exceptions both ways, unfortunately. However, BMI does have an online search engine. I’ve never used it so I don’t know its quirks, but it may be a place to start.
Downhill and Shady gives one hit.
DOWN HILL AND SHADY (Legal Title)
BMI Work #13134775
DOWNHILL AND SHADY
Songwriter/Composer Current Affiliation CAE/IPI #
LAMB LOUIS NA 0
BOOT HOUSE OF TUNES BMI 214787459