This is interesting. I always save all my statements and the papers that come with my CCs.
I got the WN Signature Card in 2007. Near the top of every statement appeared "VISA SIGNATURE SUMMARY." With the card I got a leaflet "VISA Signature Guide to Benefits," dated 1/1/06.
At some point they changed the line on the statement to "ACCOUNT SUMMARY VISA SIGNATURE."
In Sep. 2009, the word "Signature" for the first time does not seem to appear anywhere on the statement and that continued for a while. Maybe the Signature bennies were discontinued or changed at the time you got your new card?
But my 12/10 statement has the line: "Free Visa Signature perks come with your card. Call 800-953-7392 or go to visasignature.com." (worth visiting, by the way, as there are some benefits with value periodically).
Curious how these changes occur.