As stated those gears are seriously damaged. The cluster gear (also known as counter gear) is also damaged where the L/R slider comes in contact with it in the L position. It is likely the most expensive part in that transmission and could be difficult to obtain. It's possible that there are some useable parts like the syncro assembly that you could use in yours.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine