OK - Great pics - that's a Grand Godin, not a Petite. My lit with the model numbers is filed away.
It looks to be in excellent condition. The fire brick looks to not have had much use. As I said yesterday, remove the square nuts holding the top assembly and remove it. Wire brush/clean everything and re-bed it securely in stove cement, using stainless lock washers and hex nuts to reattach.
Check the grate pull ring out. The rings can detach from the rod - it's happened to me. Also, adjust the screw in latch, which secures the ash door tightly. Check-out the door gasket - I replaced mine - as well as the mica.
Carefully turn the stove upside down and clean the underside and paint it as well as reattach the feet so they don't move around - possible damage.
There are rust neutralizers made for the cylinder corrosion. Sometimes auto parts stores like Auto Zone sell them. You can try that on the cylinder to remove the rust. Otherwise, use coarse steel wool and a hand wire brush. Chemically clean the metal before applying finish.
New Godins had a semi-gloss (not matte) cylinder finish. I recommend Krylon Rust Tough R00769 Hi Temp Black over Thumalox 270, which is too matte.
On my Grands, which have non-porcelainized bases and rings, I sprayed them as well - your choice. Make sure you mask-off the porcelain really well.
I notice there is a sizing collar on the direct exhaust outlet. That increases the outlet size, and should be removable, if you want to go down to a 5" outlet. Keep it - they're hard to find.
Is there an ash pan and lift tool with the stove? The cast iron lift tool has a hook for lifting the lid and a wrench for opening the spin draft on the door. There's no secondary draft on this stove - which is one of its faults. Sometimes these tools and pans pop up on eBay. The ash pan is great to have, but I always opened the grate door and cleaned out the ash/clinkers directly, without the fire collapsing from above (not easy). This can make a lot of fly ash, but it saves the flimsy grate. Emery Pineo (Stove Hospital) has told me he's seen lots of broken Godin grates (they HATE these stoves).
That's really about it. I still like my Godins, and kind of miss their simplicity.
Hope this helps - Chris