I'm afraid that I am a bit stuck on this so I'll quote First rides from MTB Pro No. 8 from April 1994:
"The P7 is the new model in the orange stable...
...A clelebration of 7 years of the Prestige...
...a gap in the market for a stronger stiffer version of the Prestige by going slightly oversize...
...the tubes are double butted series 8...
...to be honest the difference between the P7 and the last Prestige we rode is almost indiscernable, a small hint of extra rigidity seemed relevant in that we knew about it.."
That would imply that the P7 was avalible from early to mid 1994.
It also implies that at first the P7 supplemented the Prestige rather than replaced it. I would imagine that the bike you have is indeed a P7 as it has the Series 8 tube set. (my Clockwork has series 7)
The Prestige was always built with Prestige tubes as far as I can recall.
By the time Orange dispensed with the Cable stop the Orange Prestige was already discontinued as the P7 was then 3 years established and the Prestige had no real advantage over the P7.
It is up to you weather or not you keep it badged as a Prestige when you paint it black. Personally I would if that is what you want. Though there is no shame in a P7!
I will color copy the article and post it to you later.
Hope this helps.
Somerset, like 'Heartbeat' with newer cars!
Retro MTB: 1992 Cannondale 3.0 Deore XT M730. 1992 Marin Pine Mountain Deore DX M650.
Retro road: 1992 Eddy Merckx Corsa Extra Telekom Shimano 600 STI. 1993 Dyna Tech Ti.
Modern: 2006 Wilier scandium Ultegra 6600. 2014 Wilier GTR Ultegra 6800.