Current setup is giving time stamps in 12 hr format.
This may create a confusion for projects with fast release cycle.

The requested change is a one-liner:

Index: pom.xml
===================================================================
— pom.xml (revision 32838)
+++ pom.xml (working copy)
@@ -124,7 +124,7 @@
<configuration>
<tasks>
<tstamp>

• <format property="now" pattern="MM/dd/yyyy hh:mm" unit="hour" />
  + <format property="now" pattern="MM/dd/yyyy HH:mm" unit="hour" />
  </tstamp>
  <property name="build.type" value="private" /> <!-- override for "rc" build -->
  <pathconvert property="version.rc">

References:

http://antinstaller.sourceforge.net/manual/manual/CoreTasks/tstamp.html
Java SimpleDateFormat:
H Hour in day (0-23) Number 0
h Hour in am/pm (1-12) Number 12