Gpg mime verification trouble

When someone sends a gpg mime signed message to rt. I don’t see how to get the right data out of rt to verify that signature on my machine. For example, if I send a message like this:

User-agent: redacted
From: Ian Kelling <redacted>
To: redacted
Subject: test signing in rt
Date: Tue, 13 Feb 2018 14:59:31 -0500
Message-ID: <redacted>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-=";
	micalg=pgp-sha256; protocol="application/pgp-signature"

--=-=-=
Content-Type: text/plain

aksljdf

--=-=-=
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2

iQIcBAEBCAAGBQJag0OpAAoJEBcK8OKVQpXfL5cP/1/UiStwyd+lxpaCQ7uUG93l
redacted
WmueEdV9G481KViwLDrn
=Ap3m_emphasized text__emphasized text_
-----END PGP SIGNATURE-----
--=-=-=--

I can get the signature, but I can’t get the message. What I need is this part:

"Content-Type: text/plain

aksljdf"

from the ui, i see Ticket/Attachment/WithHeaders/someid:

"content-type: text/plain; charset="utf-8"
X-RT-Original-Encoding: ascii
Content-Length: 5

asdf"

And without headers, it’s just “asdf”

I’m on RT 4.2.13-5-gc649048

I see there’s a pgp/gpg/gnupg module or somesuch for rt that can do verification, so that might be the solution, but I’m hoping that is unnecessary. https://rt-wiki.bestpractical.com/wiki/GnuPG