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From the Customs page on bringing in wood it says (Though this section doesn't address antlers, but they may consider that bone)

Can I bring or send an item made from wood to the U.S.? What if the object has feathers or bone?

Finished, manufactured, or naturally weathered products including carvings, driftwood, furniture, picture frames, and musical instruments, and plywood are allowed into the U.S., but you need to declare them so the items can be inspected by CBP. Wood that has bark attached is prohibited from China and is subject to a higher level of inspection from all countries (Miscellaneous and Processed Products Manual, Table 3-161, Pages 152-154)

Objects that have feathers are allowed if the objects are fully finished and the feathers are clean, dry, and free of skin. (APHIS Animal Product Manual, Table 3-7-13, Page 272)

Bones that are fully finished and ready to use such as buttons, knife handles, and souvenirs are allowed as are tanned hides of domestic species (APHIS Animal Product Manual, Table 3-4-6, Page 218 and Table 3-7-3, Page 262)

APHIS Animal Product Manual can be found at aphis.usda.gov.

Please note that all items made from wood, feathers, or bone may also be subject to endangered species regulations. See our Q&A entitled: Endangered species, CITES, endangered wildlife, plants, exotic skins, animals Answer ID 64.

https://help.cbp.gov/app/answers/det...ood-to-the-u.s.

If you follow the link to the product manual

http://www.aphis.usda.gov/import_exp...nloads/apm.pdf

and search for deer, they do address deer antlers, it's based on where it's coming from if it's clean, etc.