Hi Tim,
Very cool tin. Personally, I'd keep it as it is. Much rarer to find all the stamps intact, etc. The rust is a concern and you can use one of those magnifying glasses with the onboard hi intensity lights to check for holes.
The trouble with all these old tins is that they smell wonderful when you first open them but the flavors dissipate very quickly and you wind up smoking something that tastes very flat thereafter. I have commented before that back in the early 1980s a store close to me where I used to live in the UK called Gidea Park Tobacco Stores closed down and they had several large boxes of sealed 'cutter top' tins that were sold off for a pound a tin. Most of it was Gold Flake and Capstan and several other well known 1930s UK OTC blends and it was OK to smoke but went down hill pretty quickly after opening. I still can never understand the crazy money that is paid on Ebay for these tins but then I suppose its the novelty value.
And that's the other issue. Tobaccos have a lifespan, even in the tin, and then they just go strange. Even if it smells reasonably good, exposure to fresh oxygen generally kills superannuated blends very quickly. If it isn't mummy dust, it's sludge. As for the super high prices that some shell out for 50 year and older tins, well, belief in fairies dies hard, and PT Barnum was right. That said, among the sludge, wraiths, mummies, and other night terrors of ancient tobacco, I have experienced a few really remarkable smokes, but the odds are pretty long and I'm not going to pay for the privilege of gambling.