Apart from finding actual sleeves in the correct blue in good condition, look at finding the correct sleeves in any other colour as well, also difficult, to redye, since that's the only part that ties them to a blue interior.
These are not the type reproduced, albeit poorly. Certain colours reacted differently to heat, sunlight and age. Black and tan seemed to hold up best, red seemed to become brittle and fade badly and crumble, others tended to split at the seams and crack across that weak area. They can be patched, somewhat, since mostly unseen, but that's not the same.
That's probably the best set I've ever seen in blue.
