Strange choice for M2B, to display the car with the number 20. Why not choosing #14?
As Gemini saying:
Bruce McLaren Motor Racing entered the revolutionary McLaren M2B in four championship races that year (1966), using the following numbers:
#2 – Monaco Grand Prix: The historic F1 debut for the McLaren team. Bruce drove the #2 Ford-powered M2B, qualifying 10th but retiring early on lap 9 with an oil leak.
#14 – British Grand Prix (Brands Hatch): Bruce ran #14 with a Serenissima V8 engine, finishing a reliable 6th and scoring the McLaren team's very first World Championship point.
#20 – Dutch Grand Prix (Zandvoort): Assigned to Bruce for the weekend. The car suffered engine trouble during practice, resulting in a Did Not Start (DNS).
#17 – United States Grand Prix (Watkins Glen): Bruce returned to the #17 Ford-powered car, driving an excellent race to finish 5th and collect 2 more points.
#14 – Mexican Grand Prix: For the final race of the season, Bruce ran #14 again, unfortunately retiring with an engine failure.
In total, McLaren cars officially carried 2, 14, 17, and 20 on Grand Prix weekends during their inaugural 1966 season.