@dkloving: Sorry for taking a bit to get back to you! We’ve both been fully occupied with the UE4 megajam. We don’t support skeletal meshes with this system, but as n00854180t says, you can add sockets to static meshes too. However, in this case, you might be best off adding two scene components to a child class of the ModularWeapon class we supply, and using their locations instead of socket locations - this would be the simplest solution, anyway!
By the way, if you bought this system, send me a message with the email address associated with your UnrealEngine account as well as the Order ID of your purchase receipt from the marketplace, and we’ll get you added to our dedicated support slack for direct live chat support with us! 