A bit late to this post, but for future reference maybe worth it as smb 1 after the wannacry drama will probably be less and less common out there :-)
I have just used Filesys::SmbClient with smb2 or 3. You just need to fill in the file ~/.smb/smb.conf that Filesys::Smbclient autocreates with something like this:
If the share only accepts smb2, it will downgrade to 2 or 2.1, otherwise it will use 3.[global] client max protocol = SMB3
I verified this using wireshark traces.