Write SQL query to solve given problem: How many shipments with weight of no more than 1,000 pounds were shipped by the oldest truck?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(*) FROM truck AS T1 INNER JOIN shipment AS T2 ON T1.truck_id = T2.truck_id WHERE T2.weight < 1000 ORDER BY T1.model_year ASC LIMIT 1