There was a time when it was common for bike manufactures would raise the bottom bracket instead of lowering the to top tube to make a bike fit. The seat post would be the correct length but the raised BB allowed them to shorten the top tube with less tire interference.
Within reason you should be fine. I would be more concerned about reach. If you have to put the seat too far forward you will get into a bad riding position for your knees and/or you will have a tendency to to sit on the nose of the seat and put the hurt on down there. I ride bikes a little short for my legs because most of my height is in my legs. I have a 35inch inseam but only 6ft tall. That makes my comfortable reach more in line with somebody about 5'10".