People always say there's no swag at PAX.. but truth is you have to be willing to actually "hunt" for it(or in many cases, be patient and wait long times)
Some do and others don't, usually the bigger booths have plenty unless it's something really unique and coveted. I feel like most swag requires actual effort to acquire and a lot of people can't be bothered to chase it or ask.
Swag is really a treasure hunt for tenacious people who follow the tracker and go out of their way to seek it out.
Sometimes Sunday is the day where a booth will just realize there's no chance of getting rid of it all so they pull it all out and try to get rid of it. I'm sure you'll be able to find at least a few things if you are willing to seek it out.
I will be attending the whole con this year, some of the time I will be alone, but other times friends will be joining me. Mostly on SUn. though so I hope to still hook them up with some swag. Booths historically have given things away on Sunday nearing the end of the show.
So even if you can only attend the tailend you can still get something. Most booths bring things with the plans to sell everything, so they'll need to clean inventory.
Don't expect anything too crazy, but you'll probably come across a few things if you're lucky.