At this point, yes. My plan is to take the nicest parts from both and do a long term really nice build with an LS and modern amenities, then take the next best parts and do a "patina" build with the V8 and SM420 that I have in the 58 now. It is not original to the 58, but it is vintage appropriate.
I will have to decide which cab/vin gets the fancy treatment. Both cabs need work, but different work. I am leaning toward the modern build on the 59 because it has my family history. On the other hand, the 58 has a lot of significance to my kids because they helped fetch it and work on it so far.
I don't know what the right answer is yet, but I will definitely keep the pipe rack.