Wow. So the first thread I read here after a long time was the Shady Dell thread. What a mistake that was. Also, I edited this post to remove those links to products that i didn't intend to be in this thread. If you pay me...I'll advertise stuff for you. Otherwise don't put them in my posts.
Anyway, for something much less dramatic, I had the opportunity recently to weigh two C-body, 26" 3-core radiators. One is a fairly recent unit made within the past 10 years, the other an original Chrysler radiator made in mid-1965. The aftermarket unit was used and not cleaned, the Chrysler unit was recently reworked by a shop and yet to be re-installed.
Newer radiator: 19.8 lbs
Chrysler radiator: 28.2 lbs
So, the answer is..NO. The Chrysler unit contains over 8lbs more material in it's construction(and works better too, as it turns out).