Hi Tomislav!!!
I actually did consider something similar a few weeks ago. The problem is that the AS and DB engines took B4/87 Fuel.
DIANA had the DB (87) in the early stages, and all others were DC engines (C4). I cross-referenced all fuel filling signs, and unfortunautly, "C4" was on aircraft which had both tags, and also aircraft with just the one, ruling out the installation of an AS engine
So that tag could not be an engine-related...
I WISHED it was though...would have made the most sense
.
Mike