Sometimes yes, they do need a longer A time after a good nap and if he took a long time to fall asleep again after his early NW it could also suggest UT. Given that was his first (?) day doing a short am, long pm nap I would maybe just hold for a few days and see what happens, if it is a regular pattern then it will become pretty clear. I wouldn't want you to make any drastic changes after 1 day of that routine. That said, BW always says to listen to your baby, so if he really seems UT at BT you could push a bit, maybe 15mins even and hold for a few days and go from there.