Never mind. I found at Radionerds the manual for the SCR-608, 628 at

TM_11-620_SCR-608A_AND_628A.pdf

The 200 and 300 series crystals all fit these sets. The inventory list only describes a

BX-40 box for 30 crystals, so i assume only the remainder were kept at rear echelon.

-Hue Miller