Only way is to have a production model release in India or go through the Product manual in the Indian site.

AFAIK the only thing which could change is the radio transmitter. There are rules in India about transmission power and licenses required, but god knows if Nokia managed to figure those out.

EDIT: Just checked out the UG Nokia_N900_APAC_UG_en.pdf. Seems the FM transmitter is going to be working just fine.