Spot The Error....:)

This was included on a error page of more stamp pics im looking through. Can anyone tell me the error with this stamp?(just found out). Sorry the pic not that clear.

No answers?....Ok, so this is a error with the plate finishers initials actually. You can see JJMacD(John J. McDonald) and J.W.G.(James W. Gessford) initials. The stamp is from plate 14157 and the initials were actually an error - they were supposed to be JJMcD (without the a)and were changed to that after being used on just a handful of plates. I guess you could call it rare because of the few usages of that punch. Interesting....
-JC-
Thanks to Douglas S. D'Avino
http://home.earthlink.net/~davinod/Initials.htm

Is the stamp toned or is there a possibility that it was gummed both side? One unusual feature is that there were 2 plate finishers that worked on this plate.
John J. McDonald and James W. Gessford. Most plate were finished by only one person.

Yes Russ, that is also interesting that there are 2 plate finishers initials instaed of one. also Im facing that same issue as I do not have this stamp at hand yet to give answers about the gumming on both sides. Again I appoligize for not being able to have all facts without these stamps in front of me, and will now only post with stamps I have at hand.....lol...

Actually on his early plates (14074 through 14162) he used JJMacD. However from 14235 to 19014 are shown as JJMcD

Yup so he used the initials on 88 plates. But dont think it was meant in first place since his name is McDonald not MacDonald.

Russ, looks like you haven't been on in about 6 months but this stamp did end up having some light toned on front, (4 years later)..found it..heres updated pic...maybe only one known saved of the 88 tht say J.J.MacD. and of course with anothers initials..