Here's an interesting 1887 Morgan I picked up. It's got some nice dark blue rim toning, but what caught my eye is the reverse. It looks like it is a struck through dropped element. I'm not 100% sure on it, but I liked it and the price seemed reasonable. I paid $50.00 for it.
I just won this on eBay for $28.55 with free shipping: I think it's a straight Fr2 and the S-147 is a R5- variety. My other 2 are sharper, but damaged.
I assume you are just using shorthand for MS66 and MS67 and there's not some new scale I haven't heard of.