Depends. Is the photo shown from the 60s or today? If it's today, even an unused vehicle will sag on its springs, especially after almost 5 decades. Another likelihood is that the shocks are shot, as the rubber in the shocks would certainly have degraded without use over this amount of time.
One would think the heavier-duty shocks and springs for the modified vehicle wouldn't be sagging that much, though.
Who knows. I do know some station wagons from that era seem to have more sag in them than the sedans they were based on, even in the original brochures.
After reading other posts here, and looking at photos of this and other Bonneville ambulances of the era, I’d say the casket tweaked things and it never returned to original ride-height.