Do HR professionals lie?

Some of you might whiff or laugh at my question, but I'm applying for a job that requires very specific skills so it's not like the company can just replace people easily. I applied and scheduled an interview but the the HR rep I talked to did not even give me an option as to what time I could do the interview. She claimed that they were having multiple interviews and that the time slot she gave me was the only time available. I know I may sound naive, but is it possible that she could be bluffing just to get me motivated to do my best on the interview? I looked at the date the job was posted and it has been posted for a quite some time and in fact the job posting is still up on their website. Could there really be a lack of qualified applicants or could it be possible that they're just making the effort to hire the best candidate possible?