They may (or may not allow it). Though, you'll really won't know until the con is happening and you get it inspected there. (As your all ready aware of they don't approve before con). The best you can do is review their "Prop Policy"
and check the "Prohibited Items List
to get an idea if you think they'll approve it or not. There isn't much else you can do unfortunately until the weekend of the con.
(IMO) I think they might allow it. But, again it's all up to if they approve it or not at the con.