As I said, I doubt it. It's certainly not a "fact" in that anyone in the comic or Rich on the boards has stated as much.
In any event, while there are things in the first post I disagree with (pegging Durkon at exactly level 15 and Belkar at exactly level 16, for one thing), for Roy it only says that he's level 12+ (because he has neither cast a seventh or eighth-level spell, nor announced that he has the feat Improved Precise Shot with all-rogue levels, nor made a joke about old-D&D attack ranks which is being taken to mean way more than it should); if he's level 16, that's 12+. Rich has not made a joke about Roy being lower level than the rest of the Order in the quite-some-time since Roy was resurrected. He still could, at any time, of course, but the longer he goes without doing so the more likely it seems that he never will. And his wanting to make such a joke is the only reason he would have Roy be lower level than the rest of the Order.