Are they able to tell the difference between a hibernating hamster and a dead one? My gf is super worried and doesn’t really have money to go to a vet to find out

You can take it to them. Aa far as I know you don't have to pay for this.

Merwin is always free. There is a donation box as you leave the vet room to the right. $20 is suggested if you can leave a dollar leave a dollar. But you do not have to leave money. The only thing that is not free is medication, but that is deeply discounted. If they cannot help you they will refer you. As for the hamster they should be able to help your girlfriend🐹 be mindful of the hours- the doors do not open until then and then it's first come first serve so bundle them both up🤗