Sure you can go. Dress up. Slacks shirt and tie.
They might look wary if they see you are a "worldly" person and will try to discern if you are an "apostate".
On the other hand, they might be friendly because they hope you will join. I'm not sure what the response will be if you say you're an atheist and doing research.
Sunday is the WT study and public talk where most "worldly" people would be expected to show up to. Middle of the week studies are more for the congregation.
But hey, have an interesting time, just don't believe everything that is on the surface of this religion. Other information about this religion can be found on JW.facts.
They won't make you give a donation - they don't pass plates but they will hint that you should.