When Ross Martin turns over in an end table in his apartment, the studio prop rental markings are clearly visible. When he later turns the table back over, the markings are gone (either having been taped or painted over).
When Paul Marlin asks for a scotch and then a double scotch, the bartender carefully pours it into a measure and then from that into the glass, but when Roger Wiley asks for a scotch and water he pours it directly into the glass with no such care.