Need To Learn How To Differentiated Plates

Hi every one,i have a big problem,because I do not know how to differentiate plate I from plate III and there is something that bothers me,is announce like mint no gum but those yellow spots all over the stamp,mmmmm,the guy already sold me a 156 MNG but wen it comes back from the APS the cancel was erased,he paid every thing,expertise mail and the rest,but I don,t want to go through again,so any comments welcome,and good Sunday for every body
naufrago

Everything about this stamp you could possibly need to know:

https://stampsmarter.org/learning/d...dNeinken.php

Isn't that a portion of red cancel in the UL corner?

Hi,Rogdcam,thanks I will try to learn that,and what about the stamp being clean up??? all those yellow dots all over the stamp are suspicious
Naufrago

I cannot see yellow dots in your pic but it is canceled is it not?