Distributor Novice

I'm as green as can be messing with distributors. Never even pulled one out of a car till now. This was pulled from my 273 4bbl, 65 Barracuda. A few probably stupid questions, but I couldn't find a distributors for dummies book.

Where under the crud can I find a distributor number? I understand some had a tag, nothing on this one. I assume it's original to the car.
I'm adding new points. The small foam pieces on the old points - I've heard you oil them? Any advice on this?
Anything special I should look for or do to it while I have it out? I've seen penetrating oil squirted down the shaft, etc. Does anyone see anything that doesn't look right?
What is the little vent hole with the spring loaded cap all about? Last pic, lower right side of top portion.

Thanks!

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