99's are cool...still relatively cheap in general, and so many makers/variations, you can build a nice collection, and enjoy the thrill of the hunt for a good while....
While you can usually find guns at good prices, if they don't have all the goodies, the secondary market on them is nuts...original monopods, dustcovers, and cleaning rods get spendy, as do the plastic muzzle covers and original slings.
But don't think you need to grab a monopod or dust cover...they did away with them as production went on, so certain series they disappear...so you can have a rear band with the mount for the monopod, but no monopod, and that may be correct for that rifle...so don't make your rifle "wrong" by adding stuff that may not be correct...
I will try to figure what series that gun is, and let you know what it should and shouldn't have...