H1b transfer while in india with just case number WACXXXXXX

I have a valid H1b approved in 2013. I have not gone for stamping. My employer A who has applied for my H1 has not given I797 to me. The only thing i know is my case number. Can any other company B file a cap exempt petition for me while i am still in india

Yes, they can as long as your know the receipt number.