I tend to look at vacuum canisters on eBay regularly, and can say that this particular style, with nipples of the same size, are not easy to come by. Based on my observation, I would test it; if it works, restore it. If it doesn't work, I would ask around about to see if there have been any repair success stories.
The coating does look like vinyl. To me it looks very similar to the finish on the metal battery clamp. My initial thought was to start with primer and make sure it is covered, and then try dipping in paint. I also thought about plasti dip but I think you would need to thin out the product. Then I did some looking and found that they sell a spray bomb version of plasti dip so that might be the solution. Something you can experiment with on a scrap piece of sheet metal.