You would need to get permission from the author that made the arms. If he cannot be reached, technically you cannot sell said work without obtaining said permission.
If he posted permission on the forum anywhere, or has emailed you said permission, you will need to include that in any documentation with your pack(s). This not only protects you, but consumers as well.
**EDIT** I knew I read it somewhere. Here you go, Wolf. A
direct comment from Simon himself. Hope that answeres your question.

There's no problem that can't be solved without applying a little scripting.