I don't recall hearing a name for this post-picture frame design: maybe it's a split frame?
It lasted intermittently for at least 6 months after the picture frames stopped with the January, 1973 cover dated Hulk #159. Thor #207 doesn't have a split frame, but 208-210 and 212 do. Similarly, FFs 130 and 131 are split frames, 132 and 134 aren't, but 133, 135, and 136 are.
Having started a 45 year (and counting) involvement with comic reading and collecting initially with picture frame Marvels, I'm definitely partial to the genre, so much so that I've got two sets, one slabbed and the other for reading.
That's dedication to a cause.