Steel, hard to bend and can rust, copper easy to bend but can work harden and fail. Steel line is a devil to bend to the correct angles and requires a special bender.
Best alternative, Cunifer, a copper, nickel and iron alloy. Easy to bend,won’t corrode nor work harden. Used for modern brake lines as well, including Volvo.
Have replaced my fuel lines and brake lines with it. Very easy to route and bend with your hands.
https://cunifer.com/
You might find that the clips are still there under the car, if not you can get new ones, probably at brookhouse, or at a regular auto supply , they’re fairly generic. The screw holes for the clips are undoubtedly there.
The hardline will terminate somewhere about where the distributor is. Search for pictures on the internet of Volvo Amazon Engine Bay, you’ll get some idea from those.
Here’s an excellent site with loads of info, including parts books, history and repair manuals. You could also check the sales brochures and owners manuals there might be photos of the engine bay in there too.
https://www.volvoamazonpictures.se/