Mercedes still provides these brake lines with end-fittings. You will have to shape them yourself though, so keep your original (and don't warp it during removal) so you can match their shapes before fitting.
113 420 17 28 -- Early 230SL up to chassis 008143
113 420 28 28 -- Later 230SL from chassis 008144
113 420 28 28 -- 250SL and 280SL all chassis numbers (LHD)
For 250SL and 280SL all chassis (RHD), you need two lines:
113 420 29 28 (master cyl. to coupling)
113 420 19 28 (coupling to proportioning valve)