Aaron,
Back around 1984, Raleigh Cycle Company of America offered a few frames (their "Racing" frames) with 555 SL tubing. The frames were made in Japan and were examples of fine Japanese craftsmanship. This "mystery" tubing was most likely (opinion) Tange Prestige, but the decals sure look like a Reynolds decal don't they! To my knowledge, Reynolds never made a 555 SL tubing, and besides, my 1984 Raleigh Prestige Gran Sport (555 SL) has a fork with a steerer tube plainly stamped TANGE!! It's a pretty nice frame however (opinion)!
Cheers,
Chuck Brooks
Malta (warm but rainy) NY