Fuel lines "rusting out"

Yes, it is possible to repair the lines with sections, the tubing used is the same that is used for brake lines. Without seeing them it would be hard to say if it's critical. I wouldn't wait until they leak as that could get dangerous depending on the location of the rust and where the line fails. If it failed next to the exhaust and sprayed onto it that wouldn't be good.
When I do lines I replace the entire line with new, simply because the fittings and time it takes to make the flares and cut and prep the old lines so they will seal is usually more than just running a new line.
Being steel lines they can have a lot of rust and still be okay. If you could get pictures of the bad spots it would make it easier. Another option if the lines are just surface rusted would be to scrub the loose rust off with a scotch brite pad and paint the lines with cold galvanize paint, until you had the funds/time to do a replacement.

That's the catch, until you see it you don't know how bad it really is or isn't. Depending on where you live it could be minor. Where I am in NY those lines would be replaced already, probably with the rest of the car due to the salt eating it.
Fluid film or Krown would help slow the rust down. Not sure if they would do it but you could visit the same oil change place and ask them to either show you or take pictures of the rusted lines, just to get an idea of what they are like. Or call a couple shops and ask how much it would be to put it in the air just to look at it. I used to do things like that all the time for people who were worried. Then give them an estimate for repair and replace.

I wish a NY car would last that long. We hold the records for salt use on the roads over every US state and Canadian provinces as well. Plus they use beet juice/brine nix, and various other brine mixes. May as well drive the vehicle off a dock into the ocean, it would last longer.

That is a wee bit rusty. I would change the steel line and filter. The quick connect might be seeping due to the rust on the line. They can be changed but you can also replace just the inner o-ring if they leak. What you have there are three lines. One is the fuel line with full pressure, it is the one with the filter. Then there is a fuel return line, that is the one tighter to the frame. Plus there is the EVAP line, that one carries fuel vapor from the tank. That one will turn on the CEL if it leaks.

Have seen them a lot worse though.

The line goes from the filter back to the in tank pump. There is a quick connect at that end as well. If you want to replace it and use a line that is easier to deal with than the OEM steel you could opt for NiCopp alloy line. It is a nickle copper alloy. It bends and flares like copper tubing but can be used for fuel and brake lines. It's more money but it is really easy to work with and it doesn't rust. I've replaced a lot of brake, fuel and other lines with it. It also has the ability to be polished so it looks like gold!

The connectors they used are pushed into the tubing with barbs to seal them. There will be a short rubber section that has the fitting for the steel to attach.

FINELINE makes a full replacement line set for your car FL251B Runs about $140.00 Gives you all three of the lines, new filter and is a plug and play item. The lines are all pre bent and come as two pieces so they fit without a big fight.
Rock Auto carries them.