You can use a raw weight entry if you like, just make sure it's a raw weight entry that you're logging it as, not a sparkpeople database meat entry. Yes, it makes a difference.
What do you mean "nothing is really cooking anyway"? As you point out, a steak can weigh a significantly different amount when cooked so while you're not cooking off calories, if you record a raw 100g steak as 100g of cooked meat you'll be over-recording it. It takes more than 100g raw meat to make 100g cooked meat.
Deb, in New Zealand