That's an awesome Avocado! I cook on all of mine.. that's what they were made for!
I agree with Buckie!
One possible idea for the bowl vents could be a compromise of sorts... If your wanting function, but want it looking closer to original you could always get the new dual tab vents, use aviation snips, cut one tab off, and cut the remaining one down to size and file it into shape like the old small turn tabs. Then it would look closer to "period correct". However, I've seen replacement vents on older (pre mid 70s) kettles and its no big deal. As others have said, you cant see them, and if you go low and slow, you want the vents to function. The vents on my 18.5 red are beginning to wear out, and I am holding out as long as they'll function. Eventually I'll have to replace them if I want to keep it in action.