No, the 486.248463 will not fit the YT4500 (917.28858)
46-inch snowblowers were made for the old Craftsman lawn and garden tractors (1998ish to 2005) that had the 4-point deck mount. (two deck lift points in the front) Your YT4500 has a 3-point deck mount (one rod in front, two lift rods in the rear of the deck)
There are no adapters available to make it fit.
Your tractor is compatible with 42 and 50-inch snowblowers made after 2006. BUT! Most of those snowblowers came with both the 3-point and 4-point mounting kits. Make sure the snowblower you buy came off a tractor with a 3-point deck.
ALSO! Make sure you get the mid-point plate with all the pulleys, the front brackets off the tractor, and the mounting pins off the tractor frame for the mid-plate.
Searpartsdirect has some parts left but most likely will not have parts for mounting a snowblower to the tractor.
The adapter kit has been unavailable for 15 years.
There is an adapter kit that you may find on eBay but it is for mounting a 42-inch Agrifab (486) to an MTD (247) tractor. Your tractor was made by Husqvarna (917)