Like Heyjude said, adding an ash pan can be done, but may not go easily. It depends on the how the leg sockets are oriented. Given that it's the older style ash sweep it's likely that it will require a mod (screws or hose clamps) to attach a new ash catcher.
If it we're me, I'd pass. The ash pan is going to run you more than $30, iirc. For $150 you can buy a brand new kettle with Ash catcher, two bowl handles, flip cooking grate, a lid thermometer and you can even get it in a color. $80 just isn't cheap enough for a run of the mill blackie and the headache of having to mod it, IMO.
Of course, the new grill will have a taco handle, and some people just can't live with that.