[embee]

Usually yes.

Fasteners seizing in holes is usually either due to corrosion or pick-up (metal to metal micro-welding which then tears the surfaces and will lock them in solid). Stainless steel fasteners are very prone to pick-up so you should always use some sort of lube/paste/threadlock on them.

Most threadlocking compounds are essentially liquid plastic material which sets once air is excluded. You end up with a thin layer of plastic between the threads which while it is stiff to undo, it does protect from corrosion and prevents the pick-up.

Manufacturers tend to use pre-coated fasteners for production reasons (clean/consistent etc), which can be either a patch/ring of nylon type material which is just a friction modifier in effect, or can be micro-encapsulated threadlock which is released when the fastener is fitted.

It's worth using the right grade for the application, most fasteners need only a very low strength version ("nutlock" or similar names often used, or refer to the Loctite/Henkel website), basically to stop them falling out if they come loose. High strength versions ("bearing fit" etc) can be OTT for fasteners and make life difficult getting stuff apart without risking damage. Heat will usually break them down, but you need 200C or so and you don't want to overheat other components so be cautious.