Here's an odd and not at all comforting fact: since moving to Philly, the 76ers have never closed out a series in a Game 6 at home. But, small sample size, as they are only 0-2 in such situations, with both losses coming to the Celtics in the truly epic '81, '82 ECF battles. As you already know, the 76ers led both of those series 3-1. Hmmm.
Breakdown of the Sixers' sixes below, with series wins in bold, and Finals in italics, and all facts compiled by me from Basketball-reference.com, and thus possibly wrong (me, not them).
4 - home, forcing Game 7 ('86 Bucks,'79 Spurs '71 Bullets, '65 Celtics)
0 - home, clinching
0 - road, forcing Game 7 (another thing our Sixers have never done)
2 - home, potential clincher ('82 Celtics, '81 Celtics)
5 - road, potential clincher ('01 Bucks, '01 Raptors, '81 Bucks, '77 Celtics, '68 Celtics)
3 - road, closed out ('82 Lakers, '78 Bullets, '77 Blazers)