Henry,
Please don't shoot the messenger, but the best way to determine if a revolver is fake or original is to compare to known originals, and the bast source of photographs of (mostly) known originals is to use R L Wilson's The Paterson Colt Book. Now even this book has a few fakes that were intentionally or unintentionally included in this book (Wilson was a convicted felon and some of his dealings and publications were shady as part of an elaborate ruse). I generally eschew coffee table books, but this book is useful in comparing mostly known original examples with ones such as yours, especially because of the curviness of this model and because the curves of known originals are essentially "boilerplate" and fakes deviate from the curvature in many ways due to the difficulty of identical replication.
First, as already pointed out, your barrel address does appear to be a pantograph or at least deviates from the more subtle original script.
The profile of the wedge differs from most displayed in the book, but this might be a later replacement, which would be acceptable.
The curvature of the three "steps" of the barrel deviates from known original examples in that the depth of the ogee of yours is less flowing at the first step in the forward part of the the barrel and the angle of yours is less than known examples. the second "step" of yours is less graceful or refined; the third "step" of yours leading to the interface between the frame and the barrel is steeper on yours than on originals.
Likewise, the ogee of the three curves of the frame differs from originals in that the depth of the first two on yours is greater than on known originals and also the frame surrounding the end of the screw encircles this screw in a more rounder fashion than yours does. The arc of the third curve on your frame is deeper and if were used to create a circle, the circumference of the circle corresponding to the arc of your revolver would be less than that of known originals.
The curvature of the intersection of the top of the stocks and the frame is more upright than originals, as originals contain a stock that, at its intersection with the frame, points more forward than upwards.
The profile of the handle of the ramrod deviates extensively from know originals. Especially quantifiable is the length of the "hook" extending downwards and its curvature in the vicinity of the screw. On yours, the "hook" extends further down, beyond the midpoint of the screw, whereas originals contain a "hook" that barely ends in a horizontal line coincident with the center of the screw/screw hole.
The second, or rearmost, decorative band of your cylinder is deeper than known originals.
The curvature of your revolver is less refined or graceful when compared to known originals.
These are some more noticeable deviations from normal. With the revolver in hand, I'm sure others would become evident.
Putting this all together, it is virtually impossible that your Paterson is an original No 5 Texas Model Paterson.
Again, I hate to be the bearer of bad news. Is a refund available if it is determined that this is not an original example, as I have essentially done?