MM placement looks good. However, for these in anything short of stage D you pretty much can see the secondary MM well enough to be sure what it is. Once it drifts into stage D, that's where I've found coins I'm almost totally sure are this RPM but can't positively verify as the secondary MM is quite difficult to see.
So your arrows point to the right places for die markers, another positive, but honestly I can't actually see those die markers in your photos so can't comment on whether they look right or not.
End result is I believe it might be, but really can't see any secondary mint mark nor clear die markers in the images. I'd say don't give up on it, as the difference between a normal coin and FS-502 on a coin in that condition is over $100.