Not automatically, no, except when a membership is first created.
 
When a new membership is created, the reason code you entered on the final membership information screen is stored in the New Account Code field on the MASTER record (field name is NEWACT), and in the Open Reason Code field on the MEMBER1 record (field name RSNCDEOPN) for the -000 account suffix. 
 
However, when membership data is updated (via Tool #15 Update Membership Information or Tool #3 Open/Maintain Memberships/Accounts), changing the reason code on the final membership information screen changes the field in MASTER but will NOT affect the code for the -000 sub-account.
 
HINT:  If you wish to keep them in synch, Tool #920 Update Membership/Account Reason Codes will allow you to easily update both the membership and the account reason code at the same time.