mg 1500 engine question.

I am rebuilding a 1500 from a 1979 midget. I had the block at the machine shop for 2 weeks and have begun the rebuild. The problem is that the manual (haynes) tells me I should have lockwashers under the head of the main bearing cap bolts but I dont remember ever seeing them (during disassembly).It's possible the machine shop took them off but does anyone know for sure if there are suppose to be lockwashers?
Any help would be greatly appreciated. The engine had a thrown rod when i bought it and I'm trying to prevent a disaster like that from happening again.
thanks,
James