One way of checking wich SSIS packages you've deployed on your integration server and wich version build numbers they have is by running a TSQL query against the MSDB database on the server where your integration services is running.
I found the following blogpost with a very usefull TSQL script:
http://blog.hoegaerden.be/2010/01/10/list-all-ssis-packages-deployed-on-your-integration-server/
NOTE: the query was written for SQL Server 2008. For SQL Server 2005: sysssispackagefolders => sysdtspackagefolders90 and sysssispackages => sysdtspackages90.