The following information is gathered from Passenger Equipment of the Pennsylvania Railroad, Volume 1: Coaches by Liljestrand and Sweetland:
Page 3, Paragraph 4: The Altoona Car Shops rebuilt forty cars in 1937 to arch-roof, one vestibule sixty-eight rotating reclining seat class P70g coaches, renumbering them to #4360-4399.
The singular photo example on page 22 depicts P70gR coach with number 4382.
Hope this helps, and happy PRR n scale modeling!