SAM.gov provides a list of Entity Validation Documentation Requirements. Most municipalities lack these documents.
The Vermont State Archives & Records Apostilles/Authentications office can assist with SAM.gov entity verifications. They will send a letter to SAM.gov with a copy of the municipality's charter. This method has been accepted by SAM.gov.
For assistance, call the Apostilles/Authentications office at 802-828-3709 or email them at sos.statutoryfilings@vermont.gov with your request.