Great info from all answers !
I have a one hole gasket on one I have finishing rockers today . I first thought I would have to have head totally off to determine which gasket I would need ( when I thought I might need one and still may in future ) then I saw in a thread where you could see the lip with the marks under the intake elbow. I looked on one with valve cover off I could see it easily. Now at least I know where it is and might be able to see with mirror on one without valve cover off.
Now don't have to worry about it just get the two hole. This would seem to be a better option anyway. If nothing else adds slightly to engine displacement. In that case if i were ID parts I would only stock the two hole but I am sure some would insist on replacing with exact same gasket.
Hey, Maybe we could get a Headgasket Insert about a half inch thick or thicker instead of just a gasket to increase displacement etc. as long as compression not too low to ignite and new tune. Just kidding!