The MIM tele I had, had a swimming pool route for the neck and middle pup. This way they can mount whatever pickup in the bridge and/or middle position. It didn't have a HB routing for the bridge.
A humbucker routing is wider than a tele single in most cases. I had it routed for a humbucker by a luthier.
The humbucker bridge plate was wider. When I test fitted the stock single coil bridge plate, you could see the humbucker routing sticking out.
So I don't think MIM teles have a humbucker routing if they are equippped with a single coil in the bridge.