The manufacturer's code may not mean anything, because for the 15" we also have a 09C60 and 09C61 code (along with 09C57). What I mean is the codes for the 17" may not correlate to the codes on the 15".
As for the difference, it is quite safe to say that bigger does not equate better, it is just a different manufacturer.
The LG-Philips panels for the 17"s are said to be the best.
You can tell the week of manufacture from the serial, for instance mine is W8643XXXXXX, it is a week 43 machine.