Bitcoin has almost always used address space of 2^160, and is still using it.

The only exception are those addresses that were created in 2009 (and 2010), that did have and still have an address space of  2^256.
Those addresses are the P2PK addresses. (P2PK= "pay to public key")

P2PK addresses have address space of 2^256, because there is only one public key that corresponds to one private key.