Yes, But…
It’s unlikely you’d have a regapp for it, you’d probably need to test a registry-based query. See whether this gives a True/False as expected
q: exists keys whose (value "DisplayName" of it as string = "Qualys Cloud Security Agent" and value "DisplayVersion" of it as string as version < "4.8.0.31") of keys "HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall" of native registry
If that works you could modify your install command as
QualysCloudAgent.exe CustomerId={{IDofCustomer} ActivationId={{activation ID} WebServiceUri=https://qagpublic.qg2.apps.qualys.com/CloudAgent/ {if exists keys whose (value "DisplayName" of it as string = "Qualys Cloud Security Agent" and value "DisplayVersion" of it as string as version < "4.8.0.31") of keys "HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall" of native registry then "PatchInstall=True" else ""} >> “{parameter “logFolder”}{parameter “logFile”}”