daveypoo said:
I can see this hurting resale values down the road.
Why? Lenses are valued on condition not age.
Maiaibing said:
For resale value I think its irrelevant. Does anyone (serious) buy a used lens without seeing an original reciept from the seller?
Are you serious or did you forget the sarcasm tag? I have sold several lenses and never had the original receipt.
Very recently I sold an 11 year old 16-35 f2.8 that has had a 'professional' use its entire life, I paid $1,250 for it new and sold it for $900, it had the original box, caps and hood, as well as the unused soft case, all packaging and the instruction booklet. Nobody that asked about it asked for the date code, they were only interested in the condition.
As far as I can see date codes have never been anything but a hobbyists conversation piece, they served no real purpose, Canon could trace much more detailed info from the serial number if they wanted to. If any reason for omitting them was needed I would cite cost, it cost something to put it there.