Normally, I don't like going out on a limb by blabbing about something I know very little about, but since Bobby C has asked me directly (jerk), I'll provide my guess/opinion regarding the use of T series Scout and armored cars overseas (in combat not including temporary training)...
Well, There probably weren't any of these beasties sent outside the US or saw combat. Not only were there very few of these vehicles produced, they were pretty much obsolete by the time the war started and the M3A1 was already in production about 1939. Even considering what might be the most possible scenario, a small number being stationed in the Philippines before the war, isn't even very likely to me either. So, IMHO I doubt any were sent overseas prior to hostilities starting in 1941 (for us Yanks).
With all that being said, if someone else comes up with any concrete info either way, I'm definitely interested in hearing about it.
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