does that mean this is common practice
Unfortunately, in the U.S., I have noticed that phraseology is somewhat lax sometimes, especially when it is late or early, in a small town versus a city, or when the controllers and pilots "know" each other, i.e. recognize each other.
I try to always read back the runway number, and even emphasize it a little - not for the controller so much, but for any other pilots on the frequency, to give them better situational awareness. Let's say someone was on final approach and the controller forgot and cleared you for takeoff on the same runway.....