YVK,
What is an "LBS"? I've been a Glock shooter and armorer since 1989 and don't ever recall that acronym.
Also, if you want to have some serious second thoughts, conduct the standard 1911 live fire ejection test on a Glock. It's done with a round chambered and no magazine in the gun and you should get clean ejection. The Glocks I've tested will NEVER pass the test and always dump the empty down the magazine well. I've found that magazine spring condition (by pushing up on the feed stack) is a big part of reliable Glock ejection.