Appears to be the original GFCI when house was built in '84. The wires just seem to come out of the box. There are no screws holding the wires. I think I have to cut the wires to replace / update it to a new GFCI. I hate to shorten wires unnecessarily, so I thought I should ask first. Thanks for your help.

Some really old GFIs had leads. These should be spliced to the house wiring. Just undo the splices.
Is this your case?

Yes, I believe it is. The wires from the GFCI are twisted with the wires in the circuit box. I like the added length, so I guess I'll cut these wires at the existing GFCI box to retain the added length. Thank you very much for your reply.

Yes, I believe it is. The wires from the GFCI are twisted with the wires in the circuit box. I like the added length, so I guess I'll cut these wires at the existing GFCI box to retain the added length. Thank you very much for your reply.
NO..don't do that. The wires on the GFCI are "fixture" wires. You need to replace them with the same size wiring on the circuit. Those wires were connected to the GFCI at the factory and they have only one purpose and that is to connect to that device. They cannot be reused.

They seem to be the same size, but okay, I won't. You might have something there and I'm sure you know better than I. Better safe than sorry. Thank you for your reply!