1997 Honda Accord Bent valves

Replace the Head and make sure your valve timing is correct when done

It's difficult to know what damage has occured inside the engine with these engines. So until your in there we can go from there. Lets just assume just the valves were damaged and the pistons & cylinder bore is in good condition still. You'll need to get the head gasket set from your autopart supplier. This set should include everything you'll need to replace the head gasket. Also, it will be a good idea to replace all the pulleys related to the timing belt (tensioner pulley and idler pulley). You may want to replace the water pump while your in there but only if the pump bearings feel rough or show any signs of leakage.
Make sure the head and engine block are clean and free of old gasket material. DONT USE any abrasives or razor blades on aluminum cylinder head or engine blocks. If I remember right these engine blocks are cast iron so they can take more abuse just do gouge the gasket surface area. This is my recommendation.
Let me know if you have any more questions
Thanks for the question

Yes all those gasket should be replaced during a this head gasket replacement. I suspect the machine shop is to inspect and repair the valve stem guides or any other damage (ie broken off valve bouncing inside the combustion chamber).

I would look at cost. Would it cost less to have the head repaired or replaced?
Next, a new cylinder head could be a good thing but also not a good thing. The good is its new the bad is a new head seals the combustion pressures better but puts a greater stress on the 152,000 miles pistons/piston rings potentially causing them to wear out quicker. Note this is a more of a longevity idea than instant damage or wear.
Keep in mind that there still could be more damage inside to the pistons and cylinder bore.

Did the guy who did the timing belt repair do a leak down test? When there is low compression in a cylinder(s) you want to know what side is leaking. A leak down test will introduce compressed air into the combustion chamber through the spark plug hole. The tester will indicate how much (%) pressure is being loss. If the piston is damage you would hear feel compressed air coming out of the oil filler or if it is intake or exhaust valve you would hear compressed air in the intake or out the exhaust pipe respectively.

Both compression test and leak down tester connect to the spark plug hole. Compression test you crank the engine over to measure how much pressure is developed by the engine. The leak down test just uses compressed air.