On Saturday morning, I drove the old Western Kentucky Parkway section that was recently designated as I-69. As has been mentioned here before, there is no advanced signage on any other road that you are approaching I-69 (with one exception). All of the trailblazers and overhead signs still say Western Kentucky Parkway alone. The only exception appears to be at the US 62/Eddyville exit, where there actually were I-69 trailblazer signs. Why there, I am not sure, unless the ceremony took place at that interchange.
Along I-69 itself, the confirmation signs are all small (24" I suppose), with the old WK parkway signs beside them with "Formerly" above each, with the exception at the Eddyville exit and beginning from I-24 where small I-69 signs are by themselves. No mile markers have been changed, or have any exit numbers been changed.
So it looks like that for now, the I-69 designation was done "on the cheap", with only a half-hearted effort to redesignate the roadway in the field.
I suppose at some point the rest of the signage will be updated. It may happen after sections of the roadway are upgraded to interstate standards, or after other sections have been designated as well.