I'm sure you are right about that - and given the way the Iger shop appeared to operate, perhaps we may never know for sure which books he may have contributed to in some degree - layouts, etc.
And some of the ones he did for - Atlas? - disappoint - barely recognizable, as if his heart wasn't in it, unless what I am distantly recalling were heavily over-inked by clumsier hands? So maybe there are things by him which have yet to be identified, because tey dont look like him at all.....
Do you happen to know his first published work? Is it a Fiction House book?
Judging from the checklist in the recent book, his first published comic book work would appear to be Jumbo 69 (cover date Nov 1944) followed by Jumbo 70 and Wings 52 (both with Dec 1944 cover dates).
Fixed that for you.