I would suggest probably not, but 0.22uF is a standard common value for non-electrolytics, and is relatively rare for an electrolytic - you should be able to source a 0.22uF very easily.
More of a problem is the long obselete LM3909 - do you already have one?.
Personally I would suggest making a simple two transistor astable multivibrator, that's the usual way of making a signal injector.