[TUHS] v7 tape in bitsavers vs recreated tape from Keith Bostic's v7 in TUHS

Today I was looking around for more v7 stuff of interest that I might find on the web and came across a tape image in the ATT bits directory: http://www.bitsavers.org/bits/ATT/ labeled X7252.2015_UNIX_V7.tap and an image of the reel with original and added markings. I downloaded it and sure enough, it's a bootable v7. I then compared it with my recreated tape image from the files in the Keith Bostic folder on tuhs. The 11.7MB tapes are nearly identical, with only a handful of bytes that differ at the very end of the tape: ATT tape: 54532000    000000  000000  024000  000000  000000  000000 000077  000000 54532020    052135  014020  010000  034113  056720  023524 072143  122062 54532040    141401  000000  000000  000000  000000  000000 000000  000000 54532060    000000  000000  000000  000000  000000  000000 000000  000000 54532100    000000  000000  000000  000000  000000  000000 000000  037400 54532120    000000 000000 54532123 Bostic recreated tape: 54532000    000000  000000  024000  000000  000000  000000 177777  177777 54532020 I'm wondering - 1) Does anyone know the provenance of the X7252.2015_UNIX_V7.tap 2) Do the bytes at the end of the tapes look familiar or particularly meaningful? My knowledge of 40+ y.o. tape formats is woefully lacking, but I'm curious. Will