Yes, as you might expect, it appears that Draft 802.11n is actually used in the products. The FCC report for the WRT100 router shows test results for both 20 and 40 MHz Draft 802.11n OFDM modes, including spectral plots.
So why not say so? My guess is that one of the reasons might be to avoid price erosion of Linksys' Draft 11n products. After all, if you can get the benefits of Draft 11n for a hundred bucks, why pay more?