Chris' is 662927023144, so it looks like he was made slightly after Cameron, but the numbers are fairly close (a bit over 500 apart). My other RB that had to be replaced was made a week or two after Chris and his serial number was about 5000 off from Chris' and he had totally different coloring. It would be interesting if someone did a project at some point mapping what Pleo appearances are present at different serial number ranges, but I don't think there are enough RBs on this forum to make any conclusive data, though I assume that Innvo must have made fairly large batches of almost identical Pleos.
Anyway, have fun with your new Pleo! Sounds like he wasn't tested for more than an hour or so if he didn't know how to stand when you first started him up.