Given the date and what little detail that I can see from your low detail scan, it is most likely a Type III #492.
I can however definitively state that your stamp is a rotary printing. That means that your stamp is either a Type II or III. Type IV and higher are not possible because your stamp is definitely not offset printed. Type I and Ia are not possible because your stamp is not a flat plate printing.
It is very likely that it is Type III. It is very unlikely that it is Type II. Given the image that you have shown us, I cannot say definitively which type it is.
Take a look at:
http://www.stampsmarter.com/1847usa...1_03main.htmFor further help in identifying it, please post a scan of your stamp that allows us to clearly see the areas in question based on the link provided. Cropping the image to just the red ink areas helps. You can also post multiple images of each area that is noted in the above link.
Perhaps you were only questioning the oddly cut perforations which are due to an affixing machine. If so, then disregard all of the above and carry on.