I'm running with TLS, and didn't turn on SASL.
I have openssl from pkgsrc because I built something when in-tree
openssl was not ok, but here's my smtp daemon:

$ ldd /usr/pkg/libexec/postfix/smtpd 
/usr/pkg/libexec/postfix/smtpd:
         -lc.12 => /usr/lib/libc.so.12
         -lcrypto.300 => /usr/pkg/lib/libcrypto.so.300
         -lssl.300 => /usr/pkg/lib/libssl.so.300

I have no sasl packages installed.

And I'm getting spam over TLS just fine, apparently with FreeBSD
sysctls as the user name even.

Jul 27 10:07:12 foobar postfix/smtpd[13188]: TLS connection established from iris.acsalaska.net[209.112.155.43]: TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)
Jul 27 10:07:13 foobar postfix/smtpd[13188]: 44F3A1F7E: client=iris.acsalaska.net[209.112.155.43]
Jul 27 10:07:13 foobar postfix/smtpd[13188]: 44F3A1F7E: reject: RCPT from iris.acsalaska.net[209.112.155.43]: 550 <snd_pcm_hw_params_set_periods_near@ir.bbn.com>: User unknown in local recipient table; from=<> to=<snd_pcm_hw_params_set_periods_near@ir.bbn.com> proto=ESMTP helo=<iris.acsalaska.net>