r these oem sprockets?

I can't say for sure, but they look a lot like my oem ones, and they're stock 16/48 gearing as well.

The front is stock because as far as I know no aftermarket sprocket has the rubber bushing. If the rear is the same thickness than it is 532.

That front sprocket is a stock Yamaha part for a 2003-2005 YZF-R6 or a
2006 YZF-R6S.
As stated above, the giveaway on that is the rubber damper attached to it (along with the 5SL model code molded into it).

Although I see no identification marks on it (other than the 48 for number of teeth), the rear one looks like a stock Yamaha part for the same bikes.

The gearing is written right on them: 16/48.
If you mean pitch of chain, the bikes came stock with 532.

ok i just did a little more online research. so does "5SL" mean 03-05, "5MT" mean 01-02, and "5EB" mean 99-00?

Sounds right to me.