First. I did a quick face landmarking ratio check (ear-chin, ear-ear, eye-eye, eye-nose, eye-ear), some of the numbers appear to be off compared to known Morphy photographs taken between 1859 and 1870.
Second. Another observation was just comparing the two seated versions, Morphy: https://cplorg.contentdm.oclc.org/d... versus the suspect: https://images.chesscomfiles.com/up.... I compared waste to shoulder, shoulder to table top, table top to top of head, and even though the suspect's table is further back (not by much based on the size of the top hat sitting on it), the suspect appears to be significantly taller than Morphy. I even reversed the suspect image and then compared the resting hands between the two. The suspect has longer proximal phalanges compared to Morphy's, again, indicating a size difference between the two individuals. Also, the philtrum appears larger on the suspect photograph than in other Morphy photographs. Basically the suspect has a longer face compared to known Morphy photographs, resulting in more space between the nose and the upper lip.
Third. In every, and I mean every, known photograph of Morphy, he is wearing a Southern gentleman's bow tie. All known photographs be it taken in New York, New Orleans, or Paris, Morphy is sporting a bow tie. It strikes me as being an uncharacteristic fashion choice. This one is more psychological than a measurable observation.
Based on my "quick" cursory examination, I'd have to go with "not Morphy" especially considering the known seated Morphy photograph is definitely 1859 and the suspect daguerreotype is allegedly from the same time period. Either that or Morphy grew and then shrank at some point in his life.
There may be some familial resemblance leading me to consider the possibility that the suspect in the daguerreotype may be Ernest Morphy, Paul's uncle, who did live in the North for a period time and who would be a better "fit" for a daguerreotype most likely taken in the 1840s, when daguerreotypes were prevalent, and not the late 1850s.