Age of D40 fixtures?

We had (2) Desire Lustr+ D40's donated to the high school program that I help with.  These are our first LED's that the kids have been able to work with, and I am excited to let the student programmers/designers be able to at least play with a couple fixtures.  

Curious to see if there is a way to figure out the age of them?  They look great and seem to work well, just curious their age.  

Thank you.