Hi,
I was refering the link which says
http://docwiki.cisco.com/wiki/Cucm-phone-locale-installers#CUCM_User_Locale_and_Network_Locale_support
Locale Installer (LI) Releases
There are Locale Installer (LI) releases for every CUCM and CUPS major and minor release. Standard version numbering is Major.Minor. Examples include: 7.1, 8.0, 8.5. Usually, there are no LI releases for CUCM and CUPS maintenance (major.minor(maintenance) ex: 8.0(2), 8.0(3)) or service releases (ex: 8.0(3a)su1, 8.0(3a)su2).
In your case, since u are upgrading from 10.5.1 to 10.5.2 so, there won't be any need to update locales.
regds,
aman