FIFO COSTING under manufacturing concern

Sir, my question is related to FIFO costing. FIFO is very easy to understand under trading concern.

But i have problems under manufacturing concern. My understanding is that under manufacturing concern FIFO means that Goods manufatured first are sold first.

But if we made cost of goods manufactured statement like this :-

Opening Raw material
Add: purchases
Less:closing raw material
Equals raw material consumed

Add: opening Work in process
Less:closing Work in process
Equals cost of goods manufactured

Add opening Finished Goods
Less closing Finished Goods
Equals cost of goods sold

My question is that if FIFO costing is in operation then whether we apply FIFO only on finished goods stage, that is Goods manufatured first are sold first
OR
we should also apply it at work in process (just like as we do in process costing) stage and raw material stage (earliest purchased raw material is taken to the process earlier)