In a fresh install, ptpd2 won't start because of missing options.
The rc file has no configfile default.

Here is a fix:

#!/bin/sh

# PROVIDE: ptpd2
# REQUIRE: NETWORKING DAEMON
# KEYWORD: nojail
#
# Add the following lines to /etc/rc.conf to enable ptpd
#
# ptpd2_enable (bool):  Set to "NO" by default
#                       Set it to "YES" to enable ptpd
# ptp2_configfile (str): Set to "/usr/local/etc/ptpd2/ptpd.conf" by default

. /etc/rc.subr

name=ptpd2
rcvar=ptpd2_enable

load_rc_config "${name}"

: ${ptpd2_enable:=NO}
: ${ptpd2_configfile:=/usr/local/etc/ptpd2/ptpd.conf}

required_files="${ptpd2_configfile}"

command="/usr/local/sbin/${name}"
command_args="-c ${ptpd2_configfile}"

run_rc_command "$1"