I can not tell you for sure if it will fit or not, What was originally in the treadle cabinet ?
why does the 402 not fit ?
I can tell you that the 99 is a "3/4" size machine, smaller overall dimensions and it is rare ( not unheard of) to find a treadle cabinet for them.
if you care to make an "adapter plate" you can get just about any machine on there.
Also I imagine most people here will tell you that is "Too much money" for a 99. I would personally like one in that condition and would pay that much for one, just depends on your area of the country and how common they are.
Check out this link for more info on treadle's in general and putting them on different machines.
http://www.treadleon.net/woodshop/index.html
Good luck
Dan