Does anyone has additional information when this round was first produced, by chance?
I only have the information from Jane's that it was produced prior to 1990, and that makes sense as original producer Les Poudreries Reunies de Belgique bankrupted that year and it was eventually purchased by French.
Belgium has declared 115,210 M483A1 DPICM artillery projectiles when they banned cluster ammunition, but it is not clear whenever those are imported or mis-labeled NR 269. The Dutch company Eurometaal NV was licensed by a US manufacturer to produce M483A1 155mm DPICM for NATO nations in its facility in Zaandam, but first deliveries were made to the Dutch Army in 1989, which is presumably when the plant entered operation*.
*Although some European forces acquired first DPICM directly from USA, like Germany which trialed first DPICM rounds in 1983 and the first operational DM602 rounds entered service shortly thereafter, although exact date is not specified.