I don't know if your haze will have any impact (flare, lost of contrast etc.), but it definitely is not the dreaded Tele-Elmarit disease. I've seen that, and it looks like someone etched it or sandblasted it. Maybe all your lens needs is a cleaning. I suggest shooting some test shots such along with other lenses and see. KEH gives you 2 weeks to make up your mind if you'll keep the lens.
Be aware though, that the 90 T-E has visibly lower contrast @ f/2.8 that perks up nicely at f/4 and smaller. I have that lens, as well as the older "fat" version, and a pre-ASPH Summicron, so I'm familiar with the subtle differences.