LA vs Magnum accessory bolt kits

Ready to purchase a bolt kit for my Magnum build. Summit offers the bolts im looking for in a set(valve cover, oil pan, timing cover, water pump, fuel pump and distributor clamp and others) for a LA engine. Ive read that not all bolts interchange between the 2 engines. True or false? If they don't interchange which bolts are different? I know the head bolts are different. I'm using LA timing cover and water pump and oil pan. Thanks for any help!!