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What is the year and model? Is this a rwd, awd, 4wd? I assume automatic trasnmission but do you know which one?
It appears to me the shorter bolt is the one with the sealer and the longer is the one using a washer.
The two #9 at the bottom of this page, http://www.wholesalegmpartsonline.com/showAssembly.aspx?ukey_assembly=372182&ukey_make=1024&ukey_model=20287&modelYear=2007&searchString=BOLT Engine Flywheel
M11X1.5X23.5 W/SEALER and the other is M11X1.5X28 with the washer.
I believe it boils down to whether or not there was or is a spacer and I think the spacer is used with an automatic transmission most likely because a flexplate is thiner than a flywheel for a manual transmission so the one with the sealer should be the correct bolt.