The final OP for Monogatari Series Second Season (the Koimonogatari OP) is sort of an 80s-throwback sort of deal, with all the hallmarks of old anime styling - funky "lens flares", those old-school clouds, a song reminiscent of 80s-era pop, captioned lyrics - the works.
One particularly interesting feature of the OP is that it credits KAMIYA Hiroshi and SAITOU Chiwa as the voice actors of Koyomi and Hitagi, respectively.
No TV anime from the past two or three years that I have watched has (to the best of my recollection) credited a voice actor in the opening credits. The opening credits typically seem to be reserved for producers, directors, original creators, and people like that. Voice actors are, of course, credited in the ending credits, usually towards the beginning.
And so, the question: Was it more common back in, say, the 80s or thereabouts for voice actors to be credited in anime opening credits (in place of or in addition to the ending credits)?
(Or, alternatively, is this aspect of the presentation of the Koimonogatari OP just idiosyncratic / anachronistic / otherwise not in keeping with common practice from a few decades ago?)