Hmm - I know where you're coming from, ajtharp, but the stamp on the front cover contains a completely new catalogue number, and I would expect that this album, along with many others in the Platinum Plus series, was eventually reprinted and repressed with MCA labels showing MCA-37042 as the only catalogue number, with MCA being the intended label, to eliminate all trace of the old ABC labels (except for Impulse), and they were shown as MCA releases in their catalogues. In fact, Discogs has a copy (no images) showing ABCD-808 as the catalogue number, with "Tan MCA label" in the description; that could only have been pressed in 1979, as MCA bought ABC that year, and then the label design changed to the blue sky, clouds and rainbow one at the beginning of 1980, so why did they repress it in 1979 if they still had ABC copies like this one in stock in 1980, waiting to be stamped with the new number? All in all, MCA's reissues of ABC albums in that period are a real dog's breakfast - old pressings in old covers without stamped numbers, or with stamped numbers (like this one), old pressings in new covers, even new pressings in old covers! Praise the Lord if you've got a new pressing in a new cover with no stamp!
It's clearly just MCA using up the ABC stock that they inherited in the 1979 buy out.
I would move the images to the primary entry since the catalog number AB-808 is just a variant of ABCD-808. I would also add to the front cover image description that the Platinum Plus stamp was just something later added by MCA.
I've added scans from an early version of the MCA-37042 release. It has the Platinum Plus stamp on the cover with the MCA cat number, but the disc has the ABC AB-808 labels.
I wasn't sure whether to create a separate entry for this pressing; if we think that would be better, I can do that and move my images over...