Interesting video, but the guy needs to learn more about the 1848 models. The 6" barreled guns had load levers which were long enough to load the cylinder on the gun. The 1848 also had a shorter frame and a shorter forcing cone than the 1849, along with a shallow v-notch load aperture unlike the 1849, and all of the 1848 pistols did not have round/oval stop slots as many were rectangular, and some early 1849 pistols were produced and sold with a squareback TG until Colt exhausted his supply of them. I also cite a photo in Flayderman's Guide.
I don't know where he got the 1850 date for production of the so-called "Well Fargo" guns.
I think the Colt Pocket Navy .36 was not introduced concurrently with the Colt Pocket Police .36 as it would not make sense for Colt's widow to have competing pistols, especially because the Navy barrel/load lever was fairly and comparatively outdated, even though it was of stout design. I rather think the Pocket Navy was introduced post War in 1865 to try to use up parts in inventory as best as she could. A matter of conjecture.
The following is a repro 1848 Colt by Replica Arms El Paso Texas made by ASM with a date code of 1963 XIX, but I think it does well to illustrate what I have stated. I no longer own it because it is just too small to hold in hand with my long fingers.
Hope I did not step on any toes.
Regards,
Jim