Actually, Colts could be had with a variety of features. Whatever the customer would pay for. There are many 1851s with factory barrels shorter than 7 1/2". Triggerguards round or square, etc. But yes, as I mentioned, I was specifically referring to the replicas of the small framed revolver originally produced by Colt.While I know that COLT never threw away anything they could put in somewhere else, you are referring to replicas which are not Colts so they could have any feature.
I don't think the 1849 Pocket had a square backed trigger guard. That was the 1848 Wells Fargo, the 1851 Navy, and maybe one of the older .44 Dragoon models. The 1849 Pocket had round trigger guards as far as I've seen.