While some Guitar Centers may have someone knowledgeable working there, most of them pay as little as possible, attracting people that are willing to work for that amount of pay, which is a losing strategy in the long term. (Obviously they lost Mesa Boogie, and I'm sure Gibson and PRS will get tired of GC sitting on $3000-$4000 guitars collecting dust at ceiling height. Fender and GC have been propping each other up for years, but if Fender ever decides to go in a different direction, GC will become another Music-Go-Round.) Most of the time a salesperson will just know enough about the new gear they have there to make a sale.
NO ONE would buy a real vintage instrument from them, as they don't really have the means to check if it's real. I ordered from another state what they thought was an "early 80s Strat with Duncans", and when it arrived it was a Squier with a badly installed fake logo and serial, and Duncan Designed pickups. Then I had to drive to a GC that was 40 miles away to return it.