Ltd-163 identified as ltd-166?

Hi all.
I purchased a boxed ltd-163 dvd drive but to my surprise windows XP identifies it as a ltd-166s !
Has anyone any explanation of this ?
Is there any tool that could formally identify my drive ?
Same question regarding its firmware version ?
Thanks.

http://discinfo.rpc1.org
http://www.cdspeed2000.com

The LTD-163 isn’t manufactured anymore. You got an LTD-166S.