1) Yes and No.
2) The concierge (lobby or club floor) at Poly do not have extra "pull".
3) But, there are still two that have a "dining override".
4) With the override, they can slide you into ANY table service at WDW. *
5) At any time, any date, regardless how booked.
6) Without that override, they can't really do any better for you.
7) At least, no better than you can do with phone calls.
8) If you happen to get one of them, and they like you, they usually can help.
* Exceptions are HDDR and Luau. Once booked, there is no place for sliders. All the tables are booked, so sliding you in and pushing back other ADR's is not possible like in other eateries. As an example, there are AT LEAST 15-20 extra tables overbooked daily for CRT (more than capacity). This pushes a lot of ADR's back.