If it's not there, then it's not there - it's not easy to miss as it's the biggest chunk of metal in the kit
I've just bought a another one from BMW for when I do trackdays - one for each end as I'd not know which end would be facing out of the kitty-litter, and as a marshal I understand what happens if the recovery crew can't find the towing eye (they tend to tie the chain to whatever piece of body work protudes the most, or put it through the nearest window - open or not)!
That would involve getting dirty - and that dirt could make its way into the car
The only reason I got mine from the dealer rather than ebay/breakers, was that I forgot about it until the afternoon before the track day and just phoned the dealer who happened to have one, so went straight over and picked it up. I'm going to get mine powedercoated/plasticoated in bright red so that it can be seen more easily
Here's one on ebay - http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330311937262