Original Galaxy Tab Issue [Korean ROM or Int'l ROM]

I bought a Galaxy TAB on my trip to shenzhen recently. The default ROM says SHW-M18OS as the image shows below:


via i.imgur.com

but on the hardware itself it says its GT-P1000 (the code for international GTab) like so:


via i.imgur.com

I believe it is rooted as I have tested with Root Checker app.

All i want to know is if I can flash CWM and Other ROMs which are based on GT-P1000 because I cant find anything for SHW-M18OS.