First of all, yes, this chapter is numbered 87. As was last month's chapter.
I assume that this was just a typo and that this is indeed supposed to be chapter 88 that I'm looking at right here, and I also assume that this will be corrected in the eventual volume release.
But hey, this is Ohkubo, the guy for whom the number 72 apparently does not exist, so when weird numbering shit happens I guess we just never know.
( Spoilers! )
I assume that this was just a typo and that this is indeed supposed to be chapter 88 that I'm looking at right here, and I also assume that this will be corrected in the eventual volume release.
But hey, this is Ohkubo, the guy for whom the number 72 apparently does not exist, so when weird numbering shit happens I guess we just never know.
( Spoilers! )