Well yes certainly you can become overtrained . Been there done that.
I do however feel it is much harder to over train when you have all key points of recovery in place. I over trained like a mfer in my late teens early 20's .
2 hrs before work 2-3 hrs in the evening at a very intense pace + a wickedly
heavy labor job in between. About an hr into the nite session i'd start getting that pissy ammonia smell to my sweat. That I believe was urea from heavy tissue breakdown. I was really well conditioned but for a time my strength crept up ever so slowly. When I started training with stimulation then recovery
without overtraining my strenth and size gains really accelerated.
I do know many many guys that think they are overtrained and are nowhere
near it. The human body is amazingly adaptable with higher limitations than
most would think. The guys that I find always talking about overtraining are the ones that really don't enjoy the training part that much.
Just my .2 Have a great day- don't train to hard! J/K.. T