Lexington will decide whether the town should buy a Scottish Rite masons’ headquarters during a Town Meeting that will open Monday night. A Special Town Meeting and an annual Town Meeting will be open in Cary Memorial Hall at 7:30 p.m. and will tackle a total of 36 warrant articles. In addition to the town’s $173.6 million budget for the upcoming fiscal year, Town Meeting will also vote on whether to authorize selectmen to purchase about 10 acres of property at 33 Marrett Road for about $11 million. On Thursday night selectmen voted their support for offering $10,950,000 for the property. Lexington officials have been in negotiations to purchase the property from the Supreme Council of the Scottish Rite masons, which is looking to sell its headquarters and move into the organization’s neighboring National Heritage Museum. Lexington Town Manager Carl Valente said last week that a new offer was submitted to the Scottish Rite earlier this month, and the town is waiting to hear back on whether it has reached an agreement. Lexington officials have discussed using the property for a community center. Town Meeting members will also vote on whether to change the town seal so that it is consistent with the seal approved in 1934 and vote on changes proposed for the town’s zoning bylaws in an effort to reorganize the laws, eliminate inconsistencies and redundancies, and bring them into further compliance with state law.