Pewter is not a metal but instead Pewter is a color that is silver and grey in color.
So no a magnet will not stick to Pewter since it's not metal and magnets will only stick to metal such as iron.
The magnet will stick to the metal that the Pewter color is painted on but the magnet will not stick to the Pewter.
The Pewter color is a grey and silver color combination but some people think that Pewter is just grey while other people think that the Pewter color is a silver in color.
But actually the Pewter color is a combination of the silver and grey colors but it can depend on the angle that you look at the color Pewter.
Sometimes to myself in some sunlight and at a certain angle Pewter looks silver in color while other times when the sun is not shining on it as much the Pewter looks more grey.