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Yes, 'HPCPack2016Update3-Full-Refresh-v6450.zip' is the slipstream install package for HPC Pack 2016 Update 3 and it includes all the updates for HPC Pack 2016.
Also, it is recommended to onboard HPC Pack 2019 Update 1 whenever possible.
HPC Pack 2019 Update 1 (6.1.7531) - 1/22/2022
Refer below links for more information:
What's New
Release Notes
Download
Azure ARM Templates
Hope that helps.
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