P&W Wasp Junior – some questions to the specialists

…I am strugling a bit with a Wasp Junior. The engine in question is said to have belonged to a particular aircraft – however, the engine book of this aircraft gives a different fabriaction numbr: 317…on the plate of the engine I see MFG. NO. MM 2246

Now I have some questions to the specialists:

Can it be established when “317” was built?
Can it be established when “MM 2246” was built?

And if you look on the plate on the engine at the bottom line: “Revisionato Fiat”… would that actually mean that the engine was overhauled in Italy with FIAT? If correct – would soembody know in what time period FIAT did such overhauls on R-985 engines?