Holbrook school officials plan to go before the board of directors of the Massachusetts School Building Authority on Wednesday in what could be a pivotal meeting for the future of the town’s school construction project. Holbrook has been working to meet an early November deadline to complete the tasks of the eligibility period in hopes of moving to the next phase and eventually securing state funding for a new school. Asked if the board intends to vote at the meeting, authority spokesman Matthew Donovan said the agenda had not been finalized. Holbrook applied for state money for a school to serve grades 7 through 12, but in July, the Board of Selectmen asked the authority for permission to include a K-8 project in a feasibility study. Some residents have advocated building a K-12 complex, and the ultimate configuration remains far from certain.