My opinion it isn’t safe unless you know what you’re getting yourself into. If you have to ask, then, NO!
After seeing all of the pictures, unless you have skills to make this safe and modify it, I stick by my original comments. If you are a skilled tinkerer, then maybe. I would not be surprised to know it had been over fired many times looking at the lack of lower air control...a real moveable control. Looks like a throw it in a forget it type of accident waiting to happen for the lesser experienced. I certainly would not pay someone for me to get it out of their way...again, unless you have the skills. That’s a different story. Some guys can turn a turd into a bar of gold. But that is just one guy’s opinion.
For the size of the thing, I believe you can do better with an old Fisher or something as such. An old Fisher Insert is perfect for a big garage. Now, I'm only referencing the Fishers but there are many other brands out there. (To me), it looks like to much work to get it up to where it needs to be and possibly missing parts from the pictures I'm seeing. It also say's (SOLD) on the ad. Did you already buy it?