Good points mentioned here.
But the point to consider is, I don't think they will allow this. If they allow upgrading, then anyone can self damage any old card, get there for rma & upgrade it. Wow! too cool to consider.
That's what I though too.
I told him to ask for at least DDR3 version of 9500 GT. But I know that is not available. When I was buying my gfx card, I had asked for it in many shops, it wasn't available anywhere. So no question of it being available now.
Fun thing: the person at Rashi said that the card that was returned was 512MB card and the one being offered was 1 GB card, so obviously it was better!
I remember having read a review of the 1GB 9500 that said that the card didn't have enough processing power to use that much memory and only half of it was actually utilised, it gave 2-3 FPS more than the 512MB card