You've got a beauty there, and with that big fat "1" stamped in the bolt I would not be surprised if it was a team rifle from before or during WWI which got "left behind" by a Canadian team visiting the USA. Of course it could also be one brought down to FL by a Canadian "retiree" any time since it was built.
And of course Old Sir Charles himself retired to St. Petersburg FL and died there.
If you want a copy of "The Ross Rifle Story" PM me and I'll put you in touch with someone in Ontario who has copies from the second printing. Cost to your door would probably be about $100 USD. Only 100 copies were done and it is a big book.
You can email the moderator at
rossrifle.com and he will sign you up, where you will get commentary from the few real experts on the Ross, if you're patient.
Have a careful look around for a small mark of a crown over an "I" over "Q"
If you're sure you can get the handguard off without any damage or scratching to the stock, you may find some markings underneath. The middle band will probably need to be slid forward slightly to get the handguard off. Don't force it even slightly, but the stock should have shrunk a bit over the years and it should move easily once the screw is out.
There may be a serial number on the inside of the butt plate, and have look in the trap with a light for paper.