I bought the amp around 1981 from a store in Santa Anna CA. called Main St. Music, I had gone there to check out a Jim Kelly amp , and ended up buying the prune boogie.
at that time it had a D series (grey frame ) JBL 12 in installed and it was covered in a "tweed-ish " material that did not Hold up to the constant gigging that I was doing , and quickly had the cab re covered in black tolex.i replaced the JBL with an old style ( no logo ) EV. L 12. later I changed the speaker again to the Black shadow that you see in the photo.
This amp gave me what I was looking for over a fairly long time , and as my rig expanded ,it became on half of a two amp rig along with a boogie MK2 c combo. the amp has been to Japan , Australia , all over the South Pacific , and Latin America , as well as the United States.the Amp has the "EC" logo on the back of the chassis, and I was told it had been built for Eric Clapton , and to be honest it didn't matter to me ,and I only mention it to include everything I know about the amp. it came with hand drawn schematics from R. Smith on insurance agency stationary from Santa Rosa ca.it only been fairly recently that I realized that this amp is something of a rarity and a important link in the history of boogie amps , and a bit of a curiosity.it has been locked in the road case for the last 20 years or so and only occasionally switched on from time to time to check its general health.
I have never doubted nor have I questioned its authenticity, and I have always counted on this amp to give me what I wanted from it .I will say that I was never happy with the overdrive, and since I wasn't concerned about that when I bought it, it never was a bad thing .. I just never used it .. it wasn't practical as there was no separate OD volume, and not exactly switchable in the way we now take for granted similar to the early MK1you could set up an A B switch to the two inputs , but I never bothered about it .. I just loved the warmth of the clean channel and left it at that.
as to you r questions about Eric Clapton and George Harrison and what amps they owned , I wouldn't be the guy to ask , as I have no idea what they were playing through back in the 80's
I remember seeing images of Clapton with Marshalls ,and Vox amps with the Beatles ,but that's about all the info I have on that . as to servicing the amp , it was always Dave Freidman, or Lab systems in Hollywood.
I hope I covered your inquiries ,and thanks for your questions.