Yes it does look like that's the case. I've setup a clean install of Lansweeper, and the only entries in there are Windows entries. I don't really see why it couldn't have other OSes in it though.
So for now I've worked around this by adding the tblAssets.OSCode and tblAssets.AssetTypename to the report. I also tweaked the report by excluding rows with blank LSAgentVersion, as it returned a bunch monitors and other random devices. So FWIW, my tweaked report for LSAgent versions is:
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.Domain,
tblAssets.Username,
tblAssets.Userdomain,
Coalesce(tsysOS.Image, tsysAssetTypes.AssetTypeIcon10) As icon,
tblAssets.IPAddress,
tsysIPLocations.IPLocation,
tsysAssetTypes.AssetTypename,
tblAssetCustom.Manufacturer,
tblAssetCustom.Model,
tblAssets.OScode,
tsysOS.OSname As OS,
tblAssets.SP,
tblAssets.LsAgentVersion,
tblAssets.Lastseen,
tblAssets.Lasttried
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Inner Join tsysIPLocations On tsysIPLocations.LocationID =
tblAssets.LocationID
Inner Join tblState On tblState.State = tblAssetCustom.State
Left Join tsysOS On tsysOS.OScode = tblAssets.OScode
Where IsNull(tblAssets.LsAgentVersion, '') <> '' And tblState.Statename =
'Active'
Order By tblAssets.Domain,
tblAssets.AssetName