Honda head gasket question

Found a '95 Civic (real nice almost rust free body). It's got the d15z1 engine, 135k, auto, with water pump, timing belt, radiator, and thermostat replaced all within the past year- paperwork/ receipts to back it up. All new tires last year also and working heat and air conditioning. One owner vehicle. Asking price is $700 as seller says "the head gasket is leaking into the cooling system but can be driven (doesn't say how far) as long as coolant is added". Not sure he worded his description properly?

I know from experience that switching radiators on this gen Civic requires the overflow catch can to be re-hooked up properly as its a sealed cooling system. By doing it incorrectly would indeed give the symptoms he is describing in his ad. I'm thinking it's possible whoever hooked it all back up after the new radiator was put in, just didn't do it correctly? On the the other hand if it was hooked up correctly and the head gasket did indeed give out, how difficult of a job is this?

Keep in mind I've got a real nice running same year Civic with the same engine that I could swap out and put in this better rust free body. I've never had/done any head gaskets on any vehicle ever so this is uncharted territory for me but I'm willing to tackle this.

Thanks in advance from a newbie wrench.

Why all this? Cheap daily driver.

I've never seen a D-series that overheated that didn't turn into an oil burner afterwards. Honda must have used some weird metallurgy in the rings, or maybe just very low tension, because they turn into a technicality after an overheat. Technically there are rings on the pistons.

I've blown head gaskets into cooling jackets before. Not all that uncommon in my experience.

The job of pulling the head isn't complex. Very similar to doing a timing belt, just add removing the exhaust manifold and the head bolts. Removing the exhaust manifold is usually not a pleasant job.

From his description I doubt it's an issue with the radiator overflow tank, but it's not impossible either.