For $140 I have a chance to buy a supposedly new Delco 6.5 radiator for that has a damaged spot where something hit it and pushed in about 1/4" crushing the cooling fins. Looking at the attached photos, does it look like this can be repaired or would that push the total cost near a new one anyway? If it could be repaired, would repairing it compromise the reliability or life of the unit?

I don't see 140 bucks worth of aluminum, there - that thin aluminum is very difficult to repair, even if you could find a sure hand at soldering aluminum.
If that would even work.
Imo.

Take the pictures to a local radiator shop, see what they say.

I used to work in a rad shop, cores in that condition were a simple fix by cutting the tube just above the header and then heating the header and pulling out the old tube, then we simply soldered the hole shut on each end, the pic only shows 2 tubes damaged and shouldn't effect cooling much. The old headers were made of a tin material though and i'm not sure what that one is made from. Aluminum could be more difficult.