Well, at least "505", sn 83-0054 F-15C, demostrates an Escapac seat on page 90 of Isradecal's F-15 Baz book.I believe that "840", an earlier built F-15C, sn 80-0129, should have the same seat. On page 86 of the same book, pilot Avner Naveh gets out of the cockpit of 840, then scorring 4 MIGs, "blocking" the seat from the photo lens.