Hi Tom.  I checked it visually and it looks square to me.  Besides, there aren't any adjustments possible.  The whole thing is welded together.  It only tilts to the left up to 45-degrees, with a single wingnut to lock it in place.  Other than that, what you see is what you get.   
 
 
The whole saw is a barbarian from the past.  It's a Skil-brand saw and it is 20 years old.  It is louder than a DR300 at full tilt (I'd imagine it is, anyway) and it bucks and jumps and humms and is just generally unpleasant to use.  Much like my Ex.  Oh, I went there!
Anyway, I really need a new circ saw.  Like I've already said, if the damn thing didn't have the most basic of uses I'd have junked it already.  It's a power tool and if it is working, you never throw those away, no matter what.  Thankfully, I am done building cabs for the forseeable future.  The tops/subs I've built need to make me some money now and possibly down the road, we'll see about expanding the family.  For now though, the cutting/gluing/nailing/sanding/painting is done.  Well, almost anyway...IMMEDIATELY FOLLOWING the completion of these vplates, it's all done.