You are correct.
Ravin and Centerpoint are 2 separate companies, owned by the same conglomerate.
To do the job correctly, you need to replace all 4 limbs.
However, Ravin R9 limbs are the same length, width, thickness, and deflection #s as the Centerpoint limbset. They have the same axle bearings, axles, cams, strings and cables. The limbs bolt to the riser using the exact same bolts. The bearing housings bolt on using the exact same machine screw hole pattern and the exact same fasteners. When the limbs on my CP400 broke, I contacted Centerpoint who referred me to the Ravin division, who repaired the front end. When my CP400 originally arrived at my door, it was shipped in a carton clearly marked "Ravin". Later today when I get the tractor out to do some snowblowing, I'll be happy to post pix of the box it came in if you wish, it's still out in the barn.
You are "technically" correct that the limbs aren't the same. The CP400 limbs are marked CP400, and the Ravin limbs are marked "Ravin". That's the difference.
No CP400 or Ravin owner really wants mis-marked limbs on ther bow, but someone like the OP who has a problem like he has, likely won't care. He might just paint em black an go shoot his bow.