hello, you already identified it correctly as 634, there is no further investigation necessary, no measurements.
these links will help you:
http://www.stampsmarter.com/1847usa...ntifier.htmlhttp://www.stampsmarter.com/1847usa...4vs634A.htmlDon: I have to admit that I always use google to find the information in Stampsmarter, I miss an easy content area on the start page (= link list directly visible) and a search field directly there. Also, in the search results, Google seems to give other preview texts including the heading text, also if the site title is only "Stamp Smarter". Once I find the information, your site is great. I tried with "stamp smarter 634" in Google and "634" in Stampsmarter's search.