The expected behavior would depend upon how you did the copy. If the SSD were connected directly to the new computer as direct-attached-storage (e.g., external USB or Thunderbolt enclosure) and if you used Finder to drag-and-drop the files, I think they would retain the original creation date. (Just tested, and even using Finder to connect to another Mac via file sharing seems to preserve the creation dates.)
Alternatively, if you copied the files using Terminal's 'cp' or 'scp' commands, then they would get a new creation date (unless you used the '-p' option). Other apps may have their own default behavior.
How did you copy them? Finder from an external drive, Finder using file sharing over your network, some other app, Terminal commands like rsync or cp, scp, etc.?