"Custom" tells me it was made to order for a client and to his/her requested specifications. I guess that if the guns is sold by the first owner, the second owner can't claim "custom" because he didn't order it "custom" made.
I currently have 7 flint rifles and smoothbores, all made for me--except the TVM "Early Virginia." It has a rifled OTR barrel, figured walnut stock, and an L&R round-faced lock, none of which are used on any of their EV's I've seen. Must have been "custom." Whoever ordered it must be my doppelganger, cuz I have never had a rifle fit better or handle better. I bought it to hunt with just as my knees and hips told me to give it up. I think of selling it from time to time, but all I have to do is shoulder it and it goes back in the cabinet.
As to Matt and Toni, when I bought this rifle, I contacted them to learn more about it. They graciously took time to answer my questions, even though I wasn't on the other end of the line drooling to place an order. Nice folks.