Correct, Mike. Here's the Naval History and Heritage Command website with a correct image of the insignia:
https://www.history.navy.mil/researc...-markings.html (scroll down to the "Aug 1919 - May 1942" entry.
The design of the star was clarified in Navy Department General Order No. 523 of 25 March 1923: "The construction is obtained by marking off five equidistant points on the circumference of the circumscribed circle and connecting each point to the two opposite points. The outer parts of the lines thus obtained form the points of the star and the red inner circle is made tangent to the sides of the pentagon formed by this construction. (Quoted in John M. Elliott, The Official Monogram US Navy & Marine Corps Aircraft Color Guide, Vol. 1, 1911-1939, Boylston, MA: Monogram Aviation Publications, 1987, p. 52.
As Mike points out, when constructed according to these instructions, the circumference of the red central disk will not touch the blue part of the insignia. The circle was to be five feet in diameter unless the chord of the wing was less than five feet, in which case the diameter was to be approximately the same as the wing chord. However, by the time Glen's Duck was flying, there had been a number of changes to the specified size of the insignia, so, in the absence of a contemporary photograph of BuNo 1649, the best bet is to go with the insignia as it appears on the airplane today (in my opinion).
Having already provided too much information, I can't help but mention that in Korea during Christmas of 1971, my family constructed a cardboard-and-aluminum foil star for the tree using this method (no red inner disk). Every year since, that star goes atop the tree - most recently having been put in place by our 18 and 23-year old grandsons, whose then-seven-year-old father helped make that star in 1971.
Don