Yes Metal, Yes enamel coated, Pre-cut slots.
Here's the hard part. I do have one more of these. Dont know if I can get more... well at least not right now... but I'll keep my eye out for them. I have two others of the same dimension, just different cutouts.
Its a tight squeeze, but it was sheer luck that it fit so well. I've got some more mods to add to it... but I can just add that to the never ending 'To-Do list'