'''According to the government white paper on the subject all bears were destroyed shortly on return to base. All but the last three bears suffered serious internal injuries and multiple broken bones. 'Several hundred' bears were acquired for this purpose, all of which were destroyed 'in or after the testing process, by the testing process or by gun shot to the heart to preserve cranial damage from impacts'.'''
https://books.google.com.au/books?id=WTQrAAAAYAAJ&pg=PA92&dq...
None of the bears suffered serious injuries beyond broken bones and whiplash, but they were killed and autopsied afterwards. The paper doesn't explicitly state how many bears were used, and I think hundreds might be an exaggeration, but at least a couple of dozen bears were used based on the number of tests run.
It seems like it would be prohibitively difficult to source several hundred bears when you only plan on doing a few tests. You have to buy them and then you need to find somewhere to put them. Even if money wasn't an issue (and likely wouldn't be on those Cold War budgets), just the logistics of the problem would make it unlikely they'd source more bears than they needed.
The USAF museum in Dayton Ohio has one of the escape modules on display (I saw it back in 2004-ish).
http://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-...