In article ,
OM om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote:
Cutaway of Saturn I S-IV Stage
http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-9801758.html

..."Blowout Panels (8)"?? Were these part of the actual design in the
end?

Hmm, interesting question. That suggests that they planned "fire in the
hole" staging for the Saturn I -- ignition before separation. But
technical details on the Saturn I are a bit hard to find, and I don't
know offhand just how its staging was done.

http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0100805.html
...Interesting how they illustrate the interstage skirt as part of the
S-IVB and not the IB first stage.

That was standard for the Saturns -- the interstages were built as part of
the stage above, not the stage below, although they mostly remained with
the stage below after separation.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |