I saw that magazine priced at I think $19.99 by Classic Firearms and immediately figured it had to be one of the inexpensive (Chinese made?) ones stamped "mfg. CZ" on the bottom of the base plate. Those have seemed OK for range use, but they are not the real thing. Hope I am wrong about Century's, but at that price I would be shocked to find the magazines are the genuine article.
If you do find out from them, please let us know. Crossed swords surplus mags or CZ-USA (they go for about $42) new mags would sell out almost instantly at $19.99.