Stumbled over this thread and have the two above mentiond Items in my stock
a) My copy of Americans in Europe Impulse A-36 Stereo seems to be a regular Impulse 1972 pressing with the label Impulse/abc as printed label logo
b) My copy of Count Basie and the Kansas City 7 has the normal gatefold Impulse cover but on the backside a print "MCA Records - licensed by" and that described "rainbow MCA label" inside.
As London Jazz Collector shows there were a lot of label changes inc. the MCA version over the years.
Will check my complete Impulse Stock and come back if there are more differences between the frontcover and the labe inside.