So if we're being pedantic, no Bantam with a cap lifter has a half stop. The cap lifter tool was used in the 60-70s on alox Bantams and in the 70s in cellidor Bantams and, at that time, the 84mm caplifter tool didn't have a half stop.
Being less pedantic and getting to what I think you want, the cap lifter as a tool on on the Bantam goes away with the introduction of the combo tool c. 1980 (probably a year or so earlier). The 84mm combo tool evolves a bit over time and there are three main versions of it, as shown here:
(NB: dates are for the knives pictured, not introduction of tools)The latter two versions (T2 and T3) do have half stops. T1 combo tools do not. So if you want a half stop, look for the pointy-tip combo tool. If you want to avoid the half stop, look for the original stype cap lifter (not combo) tool or the round tip combo.