I Think I Have A 613- Additional Advice?

First, I know how rare this stamp is- due in part to past posts on the issue in this forum- great tips! The stamp I have is confirmed rotary press cut corners on a flat- edges don't match- it is longer. It is perforated 11, no ink on back, offset print to the perforation on the bottom, non- sharp print gray patina. It matches every description I have found for a 613. Also, it is in a 'the American album for United States stamps' on slot 613. Are there any additional things to look for to identify? Or any tips on sending to an expert? Thanks in advance.

*** Moved by Staff to a more appropriate forum. ***

Sorry- posted to wrong topic- this website is hard to use on a phone. I let site know in wrong forum. Sorry.

Some pictures would be helpful.

Did more research- I have a 612. :( This site is super helpful in providing all of the information needed to figure it out.

Your stamp is "perf 10", so yes, I agree with your re-evaluation as a 612.

And, it turns out- thanks to the research tools provided here, I have a 610, a 611 and a 612. All were affixed to the wrong slots in the stamp book, but now I know what I have. Stay tuned- I think I have a 594 - lol. More research needed. Stamp collecting is cool.