From Rama’s VictoryEdEngine code:
AStaticMeshActor* TheSMA = your static mesh actor;
FPositionVertexBuffer* VertexBuffer =
&TheSMA->StaticMeshComponent->StaticMesh->RenderData->LODResources[0].PositionVertexBuffer;
int VertNum = VertexBuffer->GetNumVertices();
so,
int RandPoint = FMath::RandRange(0, VertNum-1);
FVector RandMeshPos = VertexBuffer->VertexPosition(RandPoint);