Welcome to the site Don. I'm not real up on the inards of the 99's, so I'm not sure if there is any difference or if they are the same. The serial will help, just X out the last two digits. If it's an 1899 take down in 22 HP it's a model H, introduced in 1912 and discontinued in 1919. If it's a 99 take down it's a model F. Some one with real knowledge will be along shortly, Joe.
