Correct! It was back when they were still in the habit of using a Bond-style vocal OP song (which they did for three films: Cagliostro, Babylon, and Fuma) and putting the Lupin tune somewhere else in the film, before they'd come up with Lupin '89 and started using it as the OP and the vocal song as the ED.
Fuma was kind of the "Never Say Never Again" of Lupin films, being made on such a cheap budget that it had neither the original voice actors for the Lupin gang, nor any Ono Yuji music at all.
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