Here are two statmentssome statements from Mark Rosewater, the Un-rules managerMark Rosewater, the Un-rules manager:
When asked why Erase (Not the Ursa's Legacy One) doesn't have new Oracle text:
The Un-sets have never been updated because they are not in Oracle. Unglued still has Summon Creature for goodness sake. I have brought this problem up and I’ve been promised that it will eventually be fixed, but that it’s a low priority item so please be patient.
And when asked why silver-bordered cards don't get Oracle text, not even trivial stuff:
It’s a matter of resources. The Un-cards aren’t used for tournament play so they are low cards on the totem pole. I hope to get them Oracle-ish text one day.
For the purposes of Delirium, how does it work in Silver-Border?
Assume logical eratta on the Un-cards for card types. Entire-cray is “creature” just in another language.
My understanding from these replies is that the Un-cards would ideally be played with the Oracle updates, but that they simply have not gotten around to posting the updates, so there's no way to know for sure exactly what the Oracle text would be.
I don't have the Reputation required to post the links indicating that he's the Un-rules manager. If that's in disupte I can post them in the comments.