However, the level of mushyness in the handling should be an excellent indicator.
I did this exercise once, covering up all instruments except for oil temp, and oil pressure and flew back in, joined and landed.
Very interesting it was too, combining the visual attitude with the "feel" of the aircraft and I made a perfect landing. I often wonder why people spiral to their death when an ASI fails or they take off with the pitot cover still on.....?