Assistance Needed To Nail Down The Plating On This One

It is a bit of a wild guess, but the closest I can come to on this one is 98R5? All I have to go on though is the Neinken drawing. It does appear to be a F relief bottom row stamp ad the mottling leads me to that also.

I think someone will be able to assist here. Challenge.

Caper, you are correct that this is a bottom-row F Relief (not Plate 10), but I do not think 98R5 is the answer. Can you tell if the smudgy blue marks at bottom left are from ink or not? I do not see any definite giveaways in the photo, but I'd give a close look at position 91L7 in the Doporto archive and see how it matches up.

Thanks for the reply Dudley.
As best as I can tell under a USB microscope it is the same ink as the stamp. Looks almost like rust spots all over the lower bottom left potion of the stamp. The Deporto plate mark (in red) for the 91L7 passing thru ornament 'R' is not there but it appears some of those marks by Deporto in purple are. For the 98R5 I could only go by the Neinken drawing for that position. I'm leaning towards your suggestion tho Dudley. I only wish the 91L7 shown was a little better.