1995 Regal - Plug wires

Doing a tune up on my Regal and noticed that that the rear three wires don't have the standard rubber "boot". they are a metal cylinder with a spring sticking out of the end, and that attaches to the plug. The replacement wires that I bought have the standard end. Whats the purpose of the metal end? Can I replace those with just the standard wires? Thanks

The metal collar is for heat. You can pull the metal end off and slide it onto the new wires.

The wires fit inside of the heat shields. Give the wire end a twist to loosen it from the plug (sometimes harder than it sounds). Remove the wire then remove the heat shield. Old wires tend to cause misfires once they have been tampered with. So it might be a good idea to install new ones. Apply dielectric grease to the inside of the spark plug boot and the coil boot to make wire removal easier the next time.