The plane's combat history was only in 1942. It returned to the US in October 1942 and was supposedly doing a war bond tour by November of 1942. Actually, such planes usually got a complete overhaul and the crews got a leave of at least 30-60 days before starting these tours. I can find newspaper articles starting in early 1943 of the plane at various stops around the country but none in 1942.
Here is a history:
https://www.pacificwrecks.com/aircra...7/41-2489.html
And another version here:
https://b17flyingfortress.de/en/b17/41-2489-suzy-q/
I think the plane made it to San Bernardino earlier than the "histories" indicate.
Note the newspaper article was written in Oct 44 and the plane was already then at San Bernardino and was stripped of her turrets. It was then being used for training mechanics.
I think the photo you have of the plane without the turrets was taken anytime from Oct 1944 on, (not necessarily post war).
As a side-note, the wife of the pilot wrote a book in 1943 about the plane and crew. "The Suzy-Q", by Prisicilla Hardison.
Here are a couple of reviews:
https://www.kirkusreviews.com/book-r...on/the-suzy-q/
https://www.goodreads.com/book/show/11392540-the-suzy-q
The book can be found on the web, e.g. Amazon, abebooks, etc.