My knowledge is not all-inclusive, but the ones I have seen all had walnut covers with shields, brass liners, and bails. Never have seen one having screwdriver blade stamped. There is also a three-blade version, 13031LR, with the third blade being a pruning style hawkbill blade. Not sure but don't think the 13031 was made during the Tested era. With Case there are few absolutes, so variants may exist, but I don't recall seeing them. Someone else may have.
Of course, there are non-electricians versions (pen instead of screwdriver blade) of the 031 bare-head jack having bone, slick black, stag, and possibly other cover materials.
Edit: Collecting Case Knives
by Steve Pfeiffer says "The standard liner material for all 31 patterns was brass; however, some older examples from the Case XX era may be found with iron liners and bolsters."