Yes, he would have to get a permit, unless it's an antique or C&R. Check MO statute 571.080. Without a permit, you both could be charged with a misdemeanor.
from
http://www.moga.missouri.gov/statutes/C500-599/5710000080.HTM:
Transfer of concealable firearms without permit unlawful--exceptions --permit valid for thirty days--violation, penalty.
571.080. 1. A person commits the crime of transfer of a concealable firearm without a permit if:
(1) He buys, leases, borrows, exchanges or otherwise receives any concealable firearm, unless he first obtains and delivers to the person delivering the firearm a valid permit authorizing the acquisition of the firearm; or
(2) He sells, leases, loans, exchanges, gives away or otherwise delivers any concealable firearm, unless he first demands and receives from the person receiving the firearm a valid permit authorizing such acquisition of the firearm.
2. A permit to acquire a concealable firearm shall only be valid for thirty days after the issuance thereof.
3. Subsection 1 of this section shall not apply to the acquisition by or transfer of concealable firearms among manufacturers, wholesalers or retailers of firearms for purposes of commerce; nor shall it apply to antique firearms or replicas thereof; nor shall it apply to curio or relic firearms as defined in section 571.010.
4. Transfer of concealable firearms without a permit is a class A misdemeanor.
(L. 1981 H.B. 296 subsecs. 1, 2, 3, A.L. 1998 S.B. 496)