Ian,
the short answer is yes, it'll use the key if a suitable key exists.
A longer answer is that fetching the data in a web browse and a windows browse uses exactly the same engine (the clarion VIEW structure) and it is this View engine that is responsible for actually getting the data (using a key if it can.)
In NetTalk you don't specify the key, but in Clarion Windows you don't really specify the key either. In both cases the View engine picks whatever key it likes, or no key if it can't find a suitable key. The Clarion windows template gives you this illusion that you're picking a key, but you're really not.
cheers
Bruce