Mullard CV2492 vs CryoValve Mullard CV2492

I will soon be purchasing a DK integrated amp. Has anyone found a difference between the Mullard CV2492 and the CryoValve Mullard CV2492? Even if you have experience with these tubes in a different hybrid integrated or pre, please let me know if the Cryovalve is worth the extra cost and/or what are the differences? I'll also be trying the Siemens CCA.
If these are the so called "Mullard" mil-specs. 1980's vintage, FORGET ABOUT THEM!