Is it really a shih tzu puppy?

I found an apricot colored puppy, that the owner claims is a maltese/shih tzu mix. He has an apple-shaped head, and is super tiny and mellow, but he sheds kind of a lot. These 2 breeds are said to not shed at all, so I wonder if it is those breeds. The owner said that the puppy is only shedding because it's summer, and they changed its food type, and it hasn't been brushed out yet. Could it really be a shih tzu? thanks!