Curious coin. Looks like a D between his hind legs. The three legged buffalo was caused by excessive die polishing but no other years have been found.
There's a 3 1/2 leg 1936-D. As for the 1927, if there isn't already a known variety it would be unlikely to go undiscovered for 90 years, but anything is possible.
Anything could have happened in the 70 years before you got them. They have been making 1937-D 3 leg fakes for over 50 years. Yours could have been a practice coin and then released. Is it a coincidence the same part of the leg is missing?
1937-D are the only known dated for 3 legs buffalo. Have you check the weight? Or if there's any sign of being altered. Is it possible for you to take a close up picture of that area to examine. It will be very interesting if it a genuine. I doubt it, but everything is possible.
The weight is within tolerances. I'm thinking it might be altered with. If there were any 1927 P three leg buffalo then it propably been discovered already. Wait for some other opinions.
If a coin is too damaged to positively identify it as having a valuable defect, it becomes a defect of no value. No way to tell it wasn't intentionally done.
