Front emblem 'P Ornament'

That's cool they still stock it. When nissan seemed to be going belly up like gm now, they wanted to make for more brand identification so the "P" for prince motors went by the boards hence the later cars badges. That was the premier division like caddy division for gm.
The car that 4xtoys is parting is a bit unique as it has a nissan wheel emblem for that year plus an original prince emblem. Marque identity was the goal of the change to nissan as they slipped behind honda in sales around that time. The other thing about the change was having the same parts across the production line to cut costs

The P has nothing to do with Prince, it just means Pulsar. Just like the S on Silvia's and the S on Skylines

lol check this out for the brand identity
http://en.wikipedia.org/wiki/Prince_Motor_Company
i'd bet on the stylized 'p' being a tribute to Prince Motor Company bought out by datsun some time back, Nissan resurrected the badge from time to time. in fact the article states that prince may still yet have some input in special product development.
here's a pic as proof it exists lol
i may be wrong though :) it is a bit different but has most of the same elements.
edit: found this similar modifiers thread which shows the original pmc logo
http://www.nissangtir.co.uk/forum/forum_posts.asp?TID=30727&PID=259385