Hi...are you sure that you're seeing gouges with removable tips? I suspect that what you've really seen is carbide tips, which fall into two types, those that cut and those that scrape. The type that cut are usually circular, shaped a bit like a thick washer, with a bevel extending around its edge and a dished shape on the upper face....these are usually used for hollowing. The type that scrape come in a range of sizes, the most common being tear-drop scrapers, but also diamond, square and circular. All of these have a slight bevel on the edge and a flat top face.
Les