Calculate the area of rectangle A.

Since $1 \text{ m} = 100 \text{ cm}$, then $1 \text{ m}^2 = (100 \text{ cm})^2 = 10000 \text{ cm}^2$.

The area of the shape of all boxes is $\boxed{\text{1.12 m}^2}$.

3.2.2

The total area for one coat is $1.12 \text{ m}^2$ (from 3.2.1).

Given that $1 \text{ litre}$ of paint covers $6.2 \text{ m}^2$.

Required area for two coats = $2.24 \text{ m}^2$.
Area covered by $500 \text{ ml}$ paint = $3.1 \text{ m}^2$.
Since $3.1 \text{ m}^2 > 2.24 \text{ m}^2$, the $500 \text{ ml}$ can of paint is sufficient to cover the shapes with two coats.

The salesman stated that a $500 \text{ ml}$ can is not enough. Our calculations show that it is enough.
Therefore, the salesman's statement is $\boxed{\text{incorrect}}$.