The Part # listed is for the "older" 1100 Series AP's but also works with the 1131. We did change some of these AP's out last summer and this Lock transferred over nicely;
Using the Security Hasp Adapter
The security hasp on the access point mounting bracket and the security hasp adapter locks the access point to the bracket. After you install the access point on the detachable mounting bracket, follow these steps to secure it with a padlock (such as a Master Lock model 120T, 121T or equivalent).