Lightroom 4 bought - lost without registering - found again after 7 years

Lightroom 4 Education Edition bought in 2012 together with Master Collection CS6. I have made an Adobe ID where the Master Collection was registered and afterwards in frequently use without problems.

Soon after that when I changed residence Lightroom disappeared in a mountain of boxes full of trash before having been registered. In December 2019 when I moved again it happened to be discovered. The CD and the box with the Product code which was bought, paid, but never used.

My question: Is this Code still valid. Can I still change it into a valid SerialNumber as I did 7 years ago with my Master collection?

Thanx for any answer!