Take it elsewhere. There really is no such thing as a tune-up in the traditional sense.
Essentially all they’re doing here is changing the spark plugs and you could get this done cheaper elsewhere.
With a '92 model car, what really should be done, and could be considered a tune-up of sorts, is that a compression check should be performed when the spark plugs are removed, the air/fuel filters/PCV valve should be serviced, and the spark plug wires should be replaced, along with the distributor cap and rotor as needed.
This of course would bump you up to and over that amount you listed, but at least you’re getting something for your money.
If the vehicle is apparently running fine, fuel mileage has not dropped off much, etc. then you could get by with plugs only if you desire.