The Baby was the first stored-program computer, i.e. the first computer to store the program instructions in electronic memory, as opposed to a physical medium like the Z3's punched film. It even says so in the article you linked.
You might on rare occasions load a bootstrap program into memory from paper tape or even by hand from the console tho.
Doesn't make sense as a distinction for "stored-program computer", since that's just called a Von Neumann architecture.