Pretty much, yeah. Lupin's good at having nice localized stories per episode. Here's all you need to know:
Lupin III: World-renowned thief with a thing for cars and women. Like a goofier evil James Bond.
Jigen: Badass crackshot with a revolver. He and Lupin are best bros.
Fujiko: Hot chick that Lupin is head-over-heels for. She uses her beauty for personal gain, often screwing over Lupin in the process.
Goemon: Stoic bushido/samurai stereotype and friend of Lupin. His sword literally cuts anything.
Zenigata: Interpol investigator who follows Lupin around the globe hoping to finally arrest him. One time he finally got him, but didn't really know what to do with himself after Lupin was to be executed.
Everyone else in the 2015 show is original. If you like it, go watch the movie Castle of Cagliostro.