Olympus 18-180 serial number...?

I'm packaging my 18-180 lens for its trip to repair and I noticed something - there's no serial number on the lens. The little depressed section where the s/n sticker is located on most Oly lenses is completely blank, no sticker present.

Thinking that the sticker might have come off somehow, I tried to check its serial number with my E620, and the E620 reports its serial number is "000000000". Weird. The warranty card says the s/n is 166043987, but there is no way to tie this back to the lens, because there's no serial number on the lens, either physically or in firmware.

I'm just wondering if this is the norm for the 18-180, or is my 18-180 an exception to the rule?

--
Brian Steele
http://mypages.spiceisle.com/brian