AFAIK you need a sctp profile only if yoy need the SCTP deeper inspection otherwise you just need the security policy
ref - https://www.juniper.net/techpubs/en_US/junos12.1x44/topics/concept/gprs-sctp-configuration-overview.html
ref - https://www.juniper.net/techpubs/en_US/junos12.1x44/topics/concept/gprs-sctp-configuration-overview.html