I'm 90% certain the old number was an FBID. The new one looks like a different FBID encoding scheme - possibly with the type info included ('p') to reduce the o

I'm 90% certain the old number was an FBID. The new one looks like a different FBID encoding scheme - possibly with the type info included ('p') to reduce the overhead of a second data fetch. FBIDs are a globally unique id system that they've been using for almost as long as they've been around, if not actually from the beginning.