A good reason to know the manufacture date is the updating that manufacturers do over time to their gear without changing model designations. Vandersteen Audio is famous for this as RV's designs are never final. As he does R&D for potential new products RV may find a crossover component, for example, that performs more admirably than what he has been using. When that happens he will often incorporate that improved part into other speakers in his line.
One of the biggest examples of his is the use of carbon tweeters. Once he perfected the design and perhaps more importantly, the manufacturing for those tweeters, they began to trickle down the line.
I recently discussed this very issue with Steve McCormack. He told me that very little in my 20 year old modded DNA-1 would be still in the amp. when I receive it from the rebuild he is currently doing on it. Not because what he did two decades ago wasn't valid at the time, but because so much has been learned and so many parts have improved over that span of time as he has worked on many different amplifier designs. The "vintage" of your kit matters!
One of the biggest examples of his is the use of carbon tweeters. Once he perfected the design and perhaps more importantly, the manufacturing for those tweeters, they began to trickle down the line.
I recently discussed this very issue with Steve McCormack. He told me that very little in my 20 year old modded DNA-1 would be still in the amp. when I receive it from the rebuild he is currently doing on it. Not because what he did two decades ago wasn't valid at the time, but because so much has been learned and so many parts have improved over that span of time as he has worked on many different amplifier designs. The "vintage" of your kit matters!