The pdfs below have plots of the BPRS energy, eta, and phi distributions for 5000 events (piminus and gamma), determined by looping through all preshower hits and selecting those with eta > -.2.  The energy distribution of the original particles was flat for 5<pt<40, and the eta distribution was flat for -.2<eta<1.2.  The plots look much as I would expect, with the exception of a peak at E=4 which appears in both.