do I have the dreaded weak GM OEM hitch?

The hitch looks like all GM hitches. I have a 2004 which supposedly is one that could fail at any moment. The hitch had years of use without any sign of a problem. I have read all the reports and looked at as many pictures as I could find of the hitches that have failed. What stood out to me was that most of the failed hitches also had a great deal of rust. Many of them also seemed to be running with heavy tongue weights. I do have a heavy tongue however my hitch has never shown any sign of rust. What I have noticed is that there was a great deal of flex when I jacked the TT to engage the spring bars. Having towed the same TT over the same roads with two different trucks I noticed the GM actually would have more porpoising action while driving over a rough road. I attributed it to the flex I was seeing while hooking up. With that in mind and for my own peace of mind I bought and installed a Curt class 5 hitch. While hitching up the first thing I noticed was that there was no flex. I have only taken one trip since installing the new hitch. Driving a route that in the past would give me noticeable bounce I found that with the new hitch my ride and therefore towing experience was much better. After selling the OEM hitch on Craigslist my out of pocket expense for the hitch and new wiring plug was minimal (less than $100), peach of mind - priceless.