My gut reaction is that a 1800lb bale should be NO problem for a tractor that size. But then you mentioned that your dealer said it would be close so I looked it up.
Sure enough your tractor is only rated to lift ~1860 lbs @ 24" behind the pins. If you are talking a 6x6 bale, you are going to be at least 36" back too.
But then I got to thinking, that spec seems awfully low for that sized tractor. HEck, my MUCH smaller and lighter kubota can do ~1500lbs @ 24" back.
So I jump on over to kioti's website (same as bobcat tractors), and look at their DK40 and DK45 (same as the two you mentioned, just a different color) and they are rated to lift ~2500lbs @ 24".
So that begs the question, if they are indeed the same tractor, then yes you can handle the bales just fine (going off kioti's spec). But WHY is bobcat using a lower rating for the 3PH specs?? It makes them not even look competitive with ANY other make of that size:confused2: