You are right about the stencil markings. When the bidding on one of them slowed down and stalled below the low estimate of $400 I placed a last-second bid hoping to snipe it while everyone else was asleep. Well, everyone else woke up and bid it up to $6250! I'm embarrassed now with my bid of less than 10% of the final hammer price, it makes me look like a cheapskate.

Siegel Sale 9022 Lot 10033
Stony Brook N.Y. Perfect impression of blue circle of dots and dashes stencil marking with blue manuscript "Nov. 14" date, matching blue "PAID" handstamp and blue manuscript "10" rate on 1841 folded letter to New York City, letter refers to a publication on John Trumbull, Extremely Fine, ex Lehman and Jarrett.