Yes, you are correct, they need to supply a whole bolt assembly to make this switch of calibers as quick and painless as possible... perhaps being done under conditions very different than sitting at a gunsmithing bench with a rifle vise.

My purpose was to secure a complete "second rifle" without the need for detailed disassembly or tools required. This satisfies all the requuirements. The choice will be determined by the conditions and this will make the choice so easy.