Mark III Guru's Needed! Marked "C+", Detailed Pics

[Brandon Breeze]

I recently picked up a Mark III 1x12 Combo, with serial 154xx, 7/1985, so it's relatively early for the III. It does have the III transformer, not PT105. Still sounds killer!

This amp has a "C+" hand written above the power chord. My local amp tech, who is Boogie certified states he has seen this before, but doesn't know if it's actually from Boogie or not.

I will be emailing Boogie here shortly, just thought I'd see if anyone out there might be familiar with any of this stuff on this particular amp.

Inside the chassis is an "IVY" signature
On the top of the chassis is a Gavin Wallby, Gavin W Allby, Gavin W Auby, can't quite figure it out
Back of the chassis: "C+", MB (Mike B.), R (Randall), Engraved "Waugh" & C1479451

I know it's not a C+, just trying to see if anyone has seen this type of stuff before.

TIA

Video of the amp at the bottom. It has that really good C+ in room feel.
Here are some pics.

Here's a video of the actual amp in question:

 

[sharirebecka]

It's complicated!

 

[JD]

The red R on back of amp means it has had the reverb mod which is a 3w resistor to the reverb circuit upgraded from the stock 2w .
The C+ on back probably someone being smart the board shots show it hasn't got the 3+ mod looks like a black dot
Its missing some caps from lead circuit and Eq that is part of the 3+mod

 

[Brandon Breeze]

The red R on back of amp means it has had the reverb mod which is a 3w resistor to the reverb circuit upgraded from the stock 2w .
The C+ on back probably someone being smart the board shots show it hasn't got the 3+ mod looks like a black dot
Its missing some caps from lead circuit and Eq that is part of the 3+mod

Straight from Mike B: