[Q] Is it safe to flash a ROM with a different CSC

Hey,

I live in the UK and bought by S3 new on ebay, which is unbranded and an international version (i believe). The box said Orange France, however i havnt had any problems using it with my UK SIM. The jelly bean update has just been released through kies for the UK version of the S3, and i was just wondering what effect flashing this ROM using ODIN would have on my phone?

i downloaded the ROM from this thread

http://forum.xda-developers.com/showthread.php?t=1902493

Thanks