Correct, but there is virtually none of the original airframes that dates back to construction in 1962. They have all been rebuilt, and reskinned multiple times.
It's still the same airframe dating back to 1962. It flies until it runs out of air frame time or has enough cracks in the air frame it can no longer be repaired. Luckily, there are quite a few H models that can be brought in from the Boneyard. And if we run out of H models, there is a number of rows of G models that can be brought up to H specs and fly on. The Gs got caught up in the Start Agreements.
There were only 102 H models ever built. I believe there are 74 of them remaining. All the rest of the B-52 fleet has been consigned to Davis Monthan, where the majority have already been scrapped, and those that remain are stripped of parts to keep the H models going. And you may want to take a gander at the boneyard, there are only TWELVE B-52's on the base. And some of those are looking pretty peakid.
In all fairness, there were 744 B-52s produced of all kinds. And ALL of the B through Gs left are at DM or have been recycled or crashed or placed on static display. There are quite a few rows of Gs left at DM as of today. But I doubt if there are any B-D models left since they would have much less in common with the H model today.
I just looked at a google earth view of DM and there are 12 B-52's. All the rest are gone.
You are looking at a very narrow map. On the map I just viewed, I saw 27 total and the map did not cover everything. There are 12 parked together and the rest are scattered throughout DM. But as the G runs out of parts for the H, even the Gs are being scrapped since they have no further use. Those 12 you see are all H models in Ready Reserve (type 1000) storage and not used for parts nor are they to be destroyed.
Look at google earth. it shows you a a more recent overhead view and you can cover the entire base. I think your map is out of date by quite a while.