. . . and have my students open it in their Student versions of ExtendSim?

No, but there is a work-around.

The Student version of ExtendSim can open models built in or shipped with ExtendSim Student or in an activated Model Developer Edition of the software, but cannot open models built and saved in a Trial version.

So, if you build a model in a Trial version of ExtendSim, purchase and activate that license, then re-save the model in the activated license so it can be opened in a Student version.

If your university is an ExtendSim Adopter or owns a Floating license of ExtendSim and you are attending class remotely, follow the instructions in Remote Installation of ExtendSim on a Client Device for a Floating License. This document instructs you on how to install ExtendSim on your device and access the ExtendSim license owned by your university.

Follow the detailed instructions in Installing & Activating - Floating Licenses to install ExtendSim on Client devices.

• The Floating license of ExtendSim is typically installed in an environment where the Client device is used by only one person. This works well for academic institutions if students and professors install ExtendSim on their own computers (the Clients) since it allows ExtendSim to be used on the network or checked out from the network (roaming) for up to 30 days.
  
  If each device will only be used by one person, follow the instructions under Client Devices • Installation & Activation of the Installing & Activating document.
• If instead you are installing ExtendSim on devices intended for use by multiple persons, such as in a lab environment, please note these special instructions:
• As you install on each multi-user computer, when you get to the ExtendSim installer’s Installing User Documents section, select a location on the target machine that the students will have read/write access to. For example, you might select C:\Users\Public\Public Documents as the Destination Folder. This will install user-modifiable files at the root of the C drive.
• To activate ExtendSim on a Client device, copy the license file (extendsim.lic) that was created during License Manager activation to the folder selected in the User Documents section of the installer. In the example, this would be C:\Users\Public\Public Documents\ExtendSim10.
• Give the Users group full (not just read/write) access to the folder that has the user-modifiable files.
• Note: At the end of their sessions, students should save their models (.mox) files to locations where other users won't interfere with and/or copy their work. However, they should use a local copy while doing work. Models will run slowly if they reside on an external drive or in the cloud.