The 25th anniversarys are not common. But the 5002/5012s are moreso- and the same speaker.
The 5002s are utility cabs, and not so bad to re-finish as you'd prefer.
The 5012s/25th anniversarys are loved, feature real veneer, quality bullnose edging, and staining them will get negative feedback from collectors and enthusiasts.
Still, they are your speakers. You have to live with them- not us.
Best advice if you do go this route is a nice sanding and a black stain, or have an auto body shop spray them piano-black gloss. Otherwise, they'll most likely come out looking pretty lousy and cheap.
Staining them black, if you want it to come out properly, is going to take some elbow grease. I bet you can do it successfully, if you are willing to invest the proper time and elbow grease into it.