Scott#544 Or Scott#545?

Happy New Year!
The stamp below has 19.1mm x 22.3mm and perf 11.
Are there any other differentiators apart from size between 544 and 545, please?
Thank you very much in advance!

aug-stamps, is there a strong reason to not consider this a 498? It would be instructive to many here to see a scan of the reverse side.

Hi John Becker!
Why not 498:
- the surface of the stamp feels different than flat plate printing, one can not feel the lines on it;
- color is a dark green in reality (my scanner is making it lighter, until such times I manage to modify the driver)
- outside of the design, the paper has a very vague blur of green, which on flat plate is unlikely.
Size wise: 19.1 mm x 22.3 mm is closer to 19x22.5 as per Scott than to any other similar ones.
Of course, I might be wrong!
Verso:

No question, flat plate printing, therefore a #498, in my opinion.

John asked you to post the back image to check for 'setoff' ink. Flat plate stamps often exhibit setoff ink when the sheets got stacked, the wet ink from the sheet underneath would transfer to the back of the top sheet.
Learn more here...
http://stampsmarter.com/learning/Ma...methods.html

I would also recommend always starting with the assumption that you have the most common stamps and then using the process of elimination. If you start with the assumption that you have rare stamps it can be harder to overcome any subjective bias.
Don

Aug-stamps, Thank you for the scan of the reverse side and sharing your thinking process. It showed what I (and others) expected to see, which was the set-off of ink typical of flat plate, thus Scott 498 - as 51studebaker explained in more detail. The image dimensions listed in the catalogs are not very reliable as noted on many other threads here - the best measurement technique for these small differences is to use other stamps of known ID as comparisons.

Thank you very much!
Point taken :)
So, Scott#498 it is!

Still learning. Will appreciate any comment or advice.
Stamp Smarter: http://www.stampsmarter.com/1847usa.../d31p11.html

So, the stamp that I have is Offset Press Scott #525?
Asking, because its measurements are 0.5mm lower: 18.5 mm / 21.5mm

yes SC 525