I would rather have at least an 82 as they changed to the modern A/C controls that year. The 81-83 models had the single row timing chain. Normally I would say it had to be changed or broken by now, but maybe not if it has sat a lot of its life.
That brings up another problem with stored vehicles. They often wind up leaking everywhere as setting causes all kinds of problems with rubber products.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician