New Caledonia "Peace And Commerce" Surcharge - ? Forgery

I have the following New Caledonian "Peace and Commerce" surgcharged stamp:



Catalogues list 25c on 75c surgcharge - Stanley Gibbons No 7 and Michel No 5 - however it is listed as rose-carmine colour with 14mm wide NCE overprint. My stamp is rather deep carmine and the NCE overprint is 17mm wide - no such stamp is listed in any available to me catalogue. Also, the fonts NCE are somehow thicker when comparing with NCE overprints from catalogues.

Is it safe to assume that I have a forgery?

I would appreciate any help.

Certainly no expert, but the letters NCE look wrong - too thick and not properly shaped. Here's one I have from the same series - the image in Yvert matches this overprint, not yours.

I have a good display of early New Caledonia that I did for Frederick Mayer on my website here:

https://www.rfrajola.com/NCE/NCE.htm

see page 24 and previous few pages to get an idea of the genuine characteristics.

Thank you gmot. Yes, It's SG 5 stamp. It is 14mm wide NCE overprint. I do not have any stamps with this overprint.

Thank you Richard for a very useful source! I've bookmarked it and will use it for further reference.

I think that what qualifies the stamp in my possession as forgery is, as gmot mentioned, the shape of the letters. The shape of the letters is wrong, the width is wrong (should be 14mm - not 17mm) and the color of the stamp is wrong (should be rose carmine, not deeper carmine).