The WMI inspector should return the property to identify the the LTSC version. From what I have seen the wmi “OperatingSystemSKU” value 125 should be the LTSB/LTSC. Please double check it !!
To retrieve that property you can use the following relevance (it returns 7 on my test system):
Q:Property “OperatingSystemSKU” of select object “* from win32_operatingsystem” of wmi