FWIW AZCarbineFan, I show in my database S'G' # 3.635xxx with a Saginaw Div. barrel as well as S'G' # 3.6489xx with 11-43 Inland barrel. I agree that it is quite possible for these barrels as well as those for which you provided links to be original to their receivers given that they were all made by G.M. and it was in the best interest of both Saginaw division and the U.S. Gov't to produce as many carbines as possible.
To address your question about collectibility of IP vs S'G' carbines, IMO the IP marked receivers, which are said to number 50,000 or so, are the most collectible of all the carbine makers, excluding rarities such as M1A1icon's, M2, M3 and Commercial Controls receiver guns. S'G' receiver carbines are very desirable owing to their relationship to IP and the fact that there were only maybe 173,000 or so manufactured, over 50,000 fewer than Rock-Ola. Of course, others such as Winchester command high prices even though they were the 2nd biggest producers of M1 Carbines.
I for one would be interested in seeing pix of your 3.24 million S'G' and/or a data sheet. Is it a post war rebuild or is it in an early original configuration?
Thanks