Actually, the seats look like later (280SL) seats, in both the thickness of the seatbacks (thick enough to have headrests attached) and the MB-Tex pattern. My 230SL is very close in VIN to this one, and has (original) seats with "thinner" seatbacks, along with a much smoother MB-Tex pattern. BTW, the brake reservoir is also from a later car.
All 113s have power brakes; 230SLs were available with power steering (my first had it, my current one doesn't). You could get most things on a 230SL that you could get on a 280SL (with some small exceptions like government-mandated safety items or a hard top rear-window defroster).
Still a very nice and pretty correct-looking car.
-David Pease
'66 French 230SL