All pilots joining FR have their experience examined by the H.O.T and then are told what entry level they will enter the company. Having 4000 hours may not diferentiate you from 250 hours depending on experience for your initial course. Courses range from Cadet level - ie no heavy aircraft time, through JAR 25 operators, OCC Courses, direct entry command etc.
Having said that, entering the company with 4000 hours means you will have a command about 3 years before the guy with 250hrs as you will only need to build your 1500hrs on the 737.