Valid placement of System.ComponentModel.DataAnnotations on properties and Encapsulated fields

Question

I'm using various syntaxes of System.ComponentModel.DataAnnotations within my Model. Wondering if there's any implications on DataAnnotations placement using this short hand syntax and also the placement seen further below where DataAnnotations are on the Attributes and not Accessor & Modifier methods.

My Model with what I believe is best practice placement for DataAnnotations and this works as expected when I add OData support to my Database Context class not posted here

public class WebOrder
{
    private Guid _id;
    private float _total;
    private string _name;         

    [Key]
    public Guid Id { get; private set; }

    [Required]
    public float Total
    {
        get { return _total; }
        set { _total = value; }
    }        

    [Required]
    public string Name { get => _name; set => _name = value; }
}

Would this placement of DataAnnotations also be considered valid

public class WebOrder
{
    [Key]
    private Guid _id;
    [Required]     
    private float _total;
    [Required]    
    private string _name;         

    public Guid Id { get; private set; }

    public float Total
    {
        get { return _total; }
        set { _total = value; }
    }        

    public string Name { get => _name; set => _name = value; }
}