Attached a snapshot of 2000-3000-4000 workshop manual. I suppose you have the 201 ci engine, same as 4000.
No difference in torques between diesel and gas.
Engines may have been swapped during the years.
Just to be sure, workshop manual says:
"...Two different thickness cylinder head gaskets have been used. On tractors built before mid 1969, the head gasket has a compressed thickness of 0.029. Later gaskets have a compressed thickness of 0.037. Because of construction differences, the earlier gasket should not be used on later engines..."