Engine repair question about 2008 Town and Country 3.8L

Okay, at the risk of triggering those who think I don’t consider this a priority, I have some progress to report. I did the rubber glove test on the van today. Well, I actually did it three times because I realized I was doing it wrong the first two times. Different wrong each time, but both still wrong.

Test 1: Glove inflated, but overflow hose still attached.
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Test 2: Overflow hose disconnected, and glove past the nipple. Glove inflated, coolant in glove.
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Test 3: Overflow attached but properly clamped off. Ran the van for the same amount of time as other tests, and there was no indication of inflation at all.
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So, if what I have read here is correct, the head gaskets are okay and my issue most likely is the intake manifold gasket. Is this a safe assumption?