I have these guards. The top is a sand cast, the center is an original and the bottom is one that you may be interested in. The bottom one is available from supplier's and is wax cast.
The one you have pictured is very similar to the wax cast guard, but to me the picture tells me that the guard is a little thicker in areas. You could purchase the wax cast guard and build up those places where it is thicker. You can use bondo to achieve this.
After modeling and modifying that guard you could send it to Mike for sand casting.