Those cans might have some age and miles on them.
Did you find out any history (that you believe)?
Another thing I noticed, the endcaps are riveted to the Carbonfiber sleeves. Be really careful drilling them out if you repack them. Which they may need. If they have high milage and are in need of repacking, especially at the inlet end, the sleeves could be pretty thin in that area.
I don't know if I'd buy older carbon fiber cans unless I trusted the seller or could go inspect them. RC51's are hard on carbon fiber. Stainless or Ti are tougher for the exhaust pulses from our twins.