I don't think they priced it right, a $30 sell price could have created a 13% bump today, a big gain on opening day can create demand from retail. It changes the whole story, Facebook should know well enough the social effects of perception, even though the fundamental story is the same. The idea is not to cash out on IPO day, it's to create a story of growth and success and then cash out a few days later as the growth has whipped investors into a frenzy.
It reminds me of my realtor who would put houses on the market extremely underpriced generate huge amounts of interest. A bidding war would ensue almost immediately amongst those emotionally attached to the 'great deal'. After the bidding war the seller would have an offer 25 to 30% higher than market. The internet equivalent is $300 ebay items listed for 99 cents. Facebook fucked the IPO up by failing to generate interest through a success story, it will recover though.
Honestly, if you're 'investing' for two days you're not interested in P/E but rather technical analysis and market sentiment, both of which are poor right now, as nothing fundamental about Facebook's business has changed in the last week.