Definitely still carousel if it doesn't fit in the overhead!
I have a funny story to share from a recent flight.

Was connecting Eagle to Eagle, from a CR7 to an E175. I already had a valet tag from the first flight and totally forgot the E175 is treated like mainline for bags. I was one of the last to board and just left my bag at the end of the jetway as if it was valet checked. Didn't realize I shouldn't have done that until I arrived at my destination. Thankfully my bag still popped out onto the baggage carousel and I was terminating there .