Simple Utility script for Unity3D that allows access for "IsDirty" method for gameobjects.

IsDirtyUtility.cs

using UnityEngine;
using UnityEditor;
using System.Reflection;
using System;

//Special thanks to Shamanim for solution
//https://forum.unity.com/threads/sorta-solved-check-if-gameobject-is-dirty.504894/#post-3967810
public class IsDirtyUtility
{
    //Cached Value
    private static Func<int, bool> _isDirtyCallback;

    private static Func<int, bool> IsDirtyCallback
    {
        get
        {
            if(_isDirtyCallback == null)
            {
                //Reflection
                MethodInfo isDirtyMethod = typeof(EditorUtility).GetMethod("IsDirty", BindingFlags.NonPublic | BindingFlags.Static);
                _isDirtyCallback = (Func<int, bool>)Delegate.CreateDelegate(typeof(Func<int, bool>), null, isDirtyMethod);
            }

            return _isDirtyCallback;
        }
    }

    public static bool IsDirty(int instanceID)
    {
        return IsDirtyCallback(instanceID);
    }

    public static bool IsDirty(GameObject gameObject)
    {
        return IsDirtyCallback(gameObject.GetInstanceID());
    }

}