Heater Core Hoses on a Beretta

1994 Chevy Beretta 6cyl. My daughter and I bought one recently, and we knew the heater core was bad. So, we're in the middle of replacing it, and need some advice- The heater core itself has no markings on it, (in vs out), the only differences are that one of the aluminum pipes are larger in diameter than the other. On the replacement that we have, they're switched! Does this mean I need to switch the hoses as well? I am preparing to replace those, as one appears to be dry-rotted anyway, but should know how long to cut this new one. Thanks in advance! (Oh, the Haynes was no help)