There is another way to tell:

https://us-kb.sage.com/portal/app/portlets/results/viewsolution.jsp?solutionid=220924260102359&page=13&position=3&q=view%20upgrades 

The InstallHistory.log stores information about the history of Sage 300 CRE installs, uninstalls, upgrades, and updates on a machine. This file is stored in ProgramData\Sage, both at the server and at the workstation.
When you install, upgrade, or uninstall your Sage 300 CRE software, it creates an entry in the log showing the date and time of the occurrence, as well as the release and build version of the software or software update.
To view the contents of the log:
1. Use Windows File Explorer to Browse to C:\PrgramData\Sage
2. Right-click on InstallHistory.log and select Open, and open with Notepad.
3. Scroll to the bottom of the log to view the latest install information.
Note: The latest information is written to the end of the log.

There is another way to tell:

https://us-kb.sage.com/portal/app/portlets/results/viewsolution.jsp?solutionid=220924260102359&page=13&position=3&q=view%20upgrades 

The InstallHistory.log stores information about the history of Sage 300 CRE installs, uninstalls, upgrades, and updates on a machine. This file is stored in ProgramData\Sage, both at the server and at the workstation.
When you install, upgrade, or uninstall your Sage 300 CRE software, it creates an entry in the log showing the date and time of the occurrence, as well as the release and build version of the software or software update.
To view the contents of the log:
1. Use Windows File Explorer to Browse to C:\PrgramData\Sage
2. Right-click on InstallHistory.log and select Open, and open with Notepad.
3. Scroll to the bottom of the log to view the latest install information.
Note: The latest information is written to the end of the log.

I checked this out on the server and it does show the patch being run:

Install Name: 23.1 Update 2
Install Type: PATCH
Release Version: 23.1 Update 2 23.1.1
Build Version: 23.1.1

Still I really wish the software would show the appropriate version number change when a patch was successfully installed without having to check inside a log file to confirm.