You don't have to pre-bend the core first, and later glue on the backing. It's the bamboo that will hold the recurve. As long as the hickory is thin enough to bend the radius without lifting a splinter, you're good to go. The bamboo will add quite some drawweight, so you can make the core thinner than you might think. If you glue up two lams of hickory and one bamboo, the bow will hold the recurves even better. With only only core of hickory, you'll loose some of the curve due to spring back. In those cases where severe spingback is to be expected, pre-bending the tips first (with steam for instance) is a good way to go, but laminating a pre-bend tip is more risky in my opinion.
As a side note - hickory is really good in tension. It does not need a backing in many cases. Only if the grain is really poor, a backing of bamboo is good. In some other occasions it can even overpower the hickory belly, creating more set than we desire.
