Love the un-modelled, Hornby should be made to produce an original MN! The rebuild was their first super detail model back in 1999(?), so they've had the chassis all this time, but still can't be @rsed to produce an original ... but they can produce another Peppercorn A1 and a Thompson B1, both existing Bachmann models.
Original - is the spam can, whether it's got modified cab, tender, whatever.
Rebuilt - the Jarvis conversions with BR standard appearance (ugly things).
Unrebuilt - no such thing, poor English. A West Country is a West Country forever, it doesn't suddenly become an 'unrebuilt West Country', just because someone rebuilds a few of them.
You don't get this with the LMS Royal Scots for example, it's either a Royal Scot or a rebuilt Royal Scot, so by default its a MN/WC/BB, or its a rebuilt MN/WC/BB, end of.
... and can't you tell I've got a hangover!
Glenn