Rinaldo: 0.37 PPG in juniors
Goulbourne: 0.39 PPG in juniors
Some of the better 'fourth' liners in the NHL over the last few years, showing their junior PPG:
Torres: 1.21 PPG
Talbot: 1.2 PPG
Paille: 1.03 PPG
Richardson: 1.02 PPG
MacKenzie: 0.98 PPG
Carcillo: 0.94 PPG
Cizikas: 0.86 PPG
Malhotra: 0.8 PPG
McClement: 0.77 PPG
Chipchura: 0.76 PPG
Lapierre: 0.73 PPG
Crombeen: 0.69 PPG
Fiddler: 0.69 PPG
Gaustad: 0.68 PPG
Martin: 0.66 PPG
Campbell: 0.66 PPG
Weise: 0.65 PPG
Prust: 0.63 PPG
Bordeleau: 0.61 PPG
Roussel: 0.55 PPG
Klinkhammer: 0.54 PPG
Bouma: 0.50 PPG
College:
Letestu: 1.24 PPG
Moore: 1.15 PPG
Condra: 0.99 PPG
Boyle: 0.88 PPG
Vitale: 0.66 PPG
Virtually non of them had below 0.5 PPG when drafted either. (if they were drafted) And a lot had seasons of 0.8 PPG or above.
To be a good NHL 4th liner in general you have to produce at a decent clip in lower level leagues... I mean, it makes sense, if you are a decent hockey player with good physical attributes and a solid two way game capable of transferring to the NHL you should really be pretty good in juniors regardless of your offensive upside simply due to hockey smarts, strength, skating etc.
Pretty much every single one of the decent 4th liners in the NHL had more upside than Rinaldo and Goulbourne when they were drafted... or signed UFA after no-one drafted them.
Taylor Leier, Radel Fazleev and Oskar Lindblom are the kind of guys who if you draft and they don't pan out perfectly could very well make great 4th liners. I mean, they all have more offensive ability than Goulbourne, have great D and were all drafted later than him.
McGinn, Chaput, Cousins, Kempe, Kalinski, Maroon, Matsumoto, Laliberté and Rheault fit that category to some extent as well, skilled players at lower levels, with varying two way games... did they all pan out? No, the odds are stacked against them to begin with...though 7/9 have made the NHL, with Cousins quite possibly doing so in the future as well... but they have a better chance of making an NHL impressions than guys who were worse than them in juniors!