Don't be quick to jump to conclusions...you may be wrong...or, you could be right.
I have always went in with an expectation and 80% of the time...Im wrong...and my best nights have been going in with no real expectation to begin with.
I hear you though...and you have a point...in her defense, if there was any interest in those dudes from her stand point...you wouldn't be meeting them!
If you choose to meet them, be the bigger person and what ever you do, don't let your inner thoughts about them become apparent...she will see you as insecure and you'll lose major interest in her eyes! Also...if you do and end up hitting it off with them and they are really just friends, you'll have them in your corner...back to the last note...if it goes bad, you'll have them in her ear sayin...sh!t, you can do better than him! I'd keep that in mind before you go.