They don't usually pop back in by themselves so I suspect it wasn't fully apart.
If the fork is fully engaged on it's pivot, AND, the TO bearing contacts the PP fingers on both sides(top and bottom),at the same time, AND does not feel funny,as in springy, AND the fork-fingers appear to be parallel to the flywheel,as in not cocked at an angle(when retracted), then I would like to say you are ok.
I've been in your shoes, and thankfully managed to get it all correct without taking the tranny down. In fact, I am so confident in getting it right that I now install the fork after the tranny is installed. In the 1970 bellhouse, there is just enough room to engage them all almost simultaneously, and then bob the end with your palm, and have the three engagement points all pop in/on at the same time, with a satisfying "cluck" sound.