Not sure what to make of this

The temp agency called today, saying they needed someone for today and tomorrow. Yes, tomorrow, as in Saturday. I asked again to make sure I heard right. But then they called back and said they canceled the assignment. Then they called me again and asked me to work tomorrow. They need a typist to type up appraisals for an appraisal company. I can't help but wonder if this is some kind of April Fools' Day joke, because I've never heard of them asking for someone to work on a Saturday. They gave me all the details though, the address, the times, the name of the person I'm supposed to report to. Part of me wants to not show up because I think I'm getting tricked, and part of me thinks I'd better show up just in case. I know I'll end up going, but I'm afraid I'm going to look like a total ass.