According to the facsimile of the Lyon & Healy 1899 Harp book (catalog), the style 21 is 69 inches tall, 34 inches wide, has 45 strings, and weighs 65 lbs. In 1899 it cost $875 brand new! Described as “Designed especially for solo playing for home or stage purposes.”
Do you know if it needs restoration? If so, I would recommend H.Bryan & Co. at oldharpsmadeyoung.com. My reason is they try to preserve as much of the original as possible, replicating parts when necessary. You can check with both companies and see what you’re comfortable with. By the way, harps of that age generally use lighter gauge strings than modern harps, so you can ask H.Bryan about that, too. You don’t want to put too much tension on an old harp’s soundboard and neck. Congratulations and have fun!