Yes. Anything less is dangerous. On a motorcycle wheel, the smaller /inner bearing race MUST be captive. the outer/larger race must be captive as well, but has multiples less leverage/loading. This was true before disc brakes required disc alignment.
Ball brgs are only 100% loaded in one plane. They are NEVER 'preloaded' out of that plane. No lateral preload.
Tapered bearings are designed to sustain multi-plane loading and are usually preloaded. Preloading is required to keep the rollers in contact with both tapered races. The more severe the multi-plane loading, the higher the preload and the shorter the bearing life. Opposed (2) tapered bearings will take designed loading from any angle.
edit for clarification-the inner spacer should be tight in between/against both inner bearing races. Between the forks, there has to be a combination of spacers and inner/smaller bearing races that 'stack' tightly.
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