Hi 500 fan,
A couple of months ago I stumbled across the information you seek. However, I did not bookmark the site as I wasn't actually after that info!!
Subsequently I have spent the last 2 hours looking again for that site with no luck. All I can say is that it is (or was) out there, and let me know if you did find the info so as to put me out of my misery.
By the way, I'm fairly sure that you are correct in saying it was originally flown in an E airframe, Cheers