Does it say 85 next to Eric? Just want to make sure that's not someone's attempt at forging his last name (though he was known the sign the year a lot of the time)..something seems off. Better get roger to have a look. My brother in law collects EC, and though I haven't seen his colletion in ages, this one seems different. Most of the sigs I've seen he dotted his i's. And it just seems that this one ends differently then normally. I could very well be wrong though, as I said its been years since I've seen a genuine EC. Best of luck with it AB.
I'm no Clapton expert, so take this for what it's worth, but I think it looks okay. It seems somewhat consistent with other exemplars, but I would not purchase this without asking Roger. I'm leaning towards authentic, though. Just my opinion.