Have the PS3 version; beautiful, runs well, sounds good.
Yes, the saved/restored 999 was modernized during its working life, and retired as
a branch line loco with smaller drivers, different boiler, electric headlight, and so on.
I wish that the museum would repaint it in its "as retired" look and number; the original paint scheme on the loco just looks silly and sad (I've seen it in person.) The loco had a long and productive life span, and should reflect history, not wishful thinking. But, then, we live in a botox culture. Heaven forbid that we should look as if we had had experiences.
"Not much of the original survives..." Hah. I would be delighted if we had that much of
a J3a Hudson in a museum.