Stamperix, yes, my wrong indeed: #183 is vermilion.
Don, this stamp has an uncommon feature in form of the double impression on the back. Of course, that doesn't make it unique in any ways.
Regarding my questions around that particular mark under the scroll, I didn't start the post with any mean intentions. As I am at the very beginning of, hopefully, a long journey in Philately, I have soooooo much to learn. My learning process is a rather autistic one, with no apparent logic or apparent system behind it - this is just how I learn. If anyone is offended by this, then please accept my apologies in advance for any sort of nuisance or discomfort it might cause to you reading my posts or comments!
One fact remains: the stamp in question has that mark which is not common on other stamps - what Scott number the stamp exactly is, it is not a life or death matter to me. My work, as childish or immature might be in the eyes of those far more advanced in Philately, has value for me. For me and perhaps for others looking to learn about stamps - even if only by learning how not to approach the identification of a stamp. As you have already pointed out in a recent post.
Therefore, I would kindly ask the many of you far more knowledgeable to:
1. be patient with me;
2. correct me if you see me posting wrong statements;
3. remember, you also have started from scratch and your learning curve might have not always gone upwards

4. my post, as stupid or childish or illogical some might find it, has been the opportunity for some very precious and valuable information to be shared! ... and this is definitely in the spirit of this forum, if I understood the rules right.