I checked my first edition rulebook. ok, it's been translated to german, but I think it will be the same in the english original.
Back in those dark days before EE, there haven't been classifications like Mortal, Undead, Infernal and so on...
In the german rulebook it is stated that the now Risen Warriors are Skeleton Warriors...and the spell quicken undead has been around at that time...so it was meant for risens, cause there have been no undeads like we know them today...I think you got it...
As I mentioned before, I think the spell wasn't edited with the conversion from 1st to 2nd edition.
I think it should be that way, that all undeads can be targeted by that spell. Otherwise if it should only be skeletons you would have to change the classifications or define what is a skeleton and what is not.
just my two cents...
