The LS has one of three transmissions: a Getrag 5-speed manual ('00-'02 V6 only); a Ford 5R55N 5-speed automatic ('00-'02 V6 and V8); or a Ford 5R55S ('03-'06, all models). Both the 5R55N and 5R55S lack a transmission dipstick.
The documentation kit that came with the LS includes a pamphlet marked "Scheduled Maintenance Guide," which lists the maintenance intervals for trucks, vans, and SUVs; passenger cars under normal conditions; and "severe duty" conditions. In the normal operations table, it shows the 30K mile tranny fluid service is only for the transmissions I listed above.
On the Lincoln Owner's site, it does, indeed, show the 30/60/etc schedule. I don't know why it differs from the printed guide.