A Black Bear is a black bear...30-06 will be more than adequate to deal with the largest black. If you're hunting with a guide in bear country I'll bet he's packing some serious bear medicine in case you encounter a brown. If I was on my own in Alaska bear country I'd probably want something beefier for security.
I still have my doubts of the ability of any hunting round to bring down a charging brown after he's decided you're dinner. Personally for that scenario I'd want a 12ga loaded with a mix of slugs and the heaviest gauge buck I could find.
If you want to properly preserve velvet antlers, you will have to inject & brush them with formaldehyde or some of the new less toxic chemicals (4 in 1 solution works great as does Knobloch's antler in velvet tan) as its easier to use however, both will work.
First, using rubber gloves take a razor blade and make small incisions at the tips of all points about 1/8". Next hang the antlers upside down, allowing the blood to drain. Starting at the bases inject the solution into the...