before for sure... right on the inside edge. you aren't worried about sealing stuff in or out of the cabinet (which is all a bead would do) you want it to glue the pieces together. the glue does the holding.
I make cocktail cabinets for sale locally, and PL and a staple gun is all I use. the staples basically hold things together while the PL dries. in all honesty, you could just clamp it and not even nail, staple, screw or whatever and it would still be just as strong.
i use the PL to glue 3/4"x3/4"x8" wood battens on the edge of one of the pieces. (staple them down) and then let them set up... then attach whatever to that piece stapling through the battens in the other direction... nothing from the outside is visible. When I first started out, I screwed them down after gluing them with PL and found it not really necessary.