I'm working on a project just now with some of these papers with a similar vintage. The Ilfobrom (G3 single weight) is still workable but at least a grade softer and very little base fog. Likewise for G3 Ilfospeed though has kept better contrast. The Ilfomar was surprisingly good with a slight warm tone, bit of base fog, though not unpleasant, and also was very interesting in lith dev. (See attached) Not a great scan or a good print, a bit too dark, though looks a bit like warm tone paper processed in pyro. However, as always depends on how it's been stored. I presume you could buy it for a cheap price as wouldn't want to spend a lot given the risk of old papers. Even heavily base fogged papers can yield interesting results given a bit of bleaching.