That is one very old saw! I couldn't find the exact saw on eBay, but Disston saws from that era go for around $200 to $400 each. Just don't clean the blade at all. There are a lot of saw collectors who will be able to remove most of that rust without harming the blade. Leave it exactly the way it is if you want to get top dollar for it on eBay.
Thanks don I did see that medallion there but if you look closer there is no dot after disston and the letter A is smaller I'm thinking that would have some significance to a collector
Good eye !
Here's another with the dot after Disston:
As to the size of the "A", the reference states: Late 1840's or early 50's medallions left and right with "H. Disston. Phila" in the stamp. Note the small size of the letter "A". This feature comes and goes for four decades, 1850's-1880's. This Federal-style was used for perhaps a decade before a stylized, Aztec type of eagle was introduced.
Don......