The TS55 I purchased in early 2006 has a slightly different base than my several newer TS55s. At some point, perhaps in 2008, black plastic shims were added to improve the guide action. Honestly I have not had any problems with the older TS55.
As far as I know that was the most recent change to the TS55 sold in the USA.
I guess I should weigh in on the topic. To my knowledge, there are no imminent plans to make improvements to or introduce a new model of the TS 55. I'm pretty confident I would know about something like that coming down the pipe.
i think it is just shadow in the picture.. I took my ts55 wich dates jan.2011 and the base is exactly the same to
the one in the picture.. The things you see, are cast iron(aluminum) ribs for stiffnes i guess..
mine does have some black plastic thingies on the bottom of the base ( festool calles them crossheaded guides (nr494588))
u can order them, probably fit in your base also..