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I think, by default, all the interconnected MPLS routers will "know" of all interface networks if also defined as MPLS interfaces. I.e. the interconnected MPLS routers will act much like one router routing between its local (connected) interfaces (because of LDP).
If you want MPLS routers to forward traffic beyond one of their MPLS defined interfaces, you'll need to get correct forwarding information into your MPLS domain. MPBGP could be used, but I also believe, by default, like BGP, it's not going to "know" of routes beyond those used for peering.
So, I believe the answer to your questions would be a MPLS PE router, by default, would only forward traffic to a connected server if the server was on a subnet that connected to a defined MPLS interface defined on that subnet. Again, much like servers connected to a router (or L3 switch) with subnets on connected interfaces.
