I'm probably cutting my own throat by doing this, but.......Based on new info I'm changing my answer to
FALSE. Final answer.
Enfield P 56/58/60 Rifle
Enfield also produced several shorter versions of its P53 rifle-musket. All had 33-inch barrels and an overall length of 48½ inches and were often called "two-band" Enfields after the number of bands securing the barrel. The Pattern 56 and 58 rifles had a light three-groove barrel, while the Pattern 60 Army rifle and the Pattern 58 Navy rifle both featured a heavier five-groove barrel with progressive depth rifling and a faster 1:48 twist, giving them superior accuracy.
The two-band Enfield quickly became the top choice for Confederate sharpshooters. "Every short Enfield which came into possession of any of our men was taken away and given to these men," said a Georgian in Gordon's brigade, "but there were not enough, and some of them had the common long Enfield. Both kinds had a long range and were very effective. The short guns were given them, as they were lighter and handier."
This particular P60 Enfield belonged to Berry Benson, a sharpshooter with McGowan's South Carolina brigade. (
courtesy Augusta Museum of History)
Edit - The question asked whether it was true or false that the Whitworth was "a" favorite, not necessarily "the" favorite of all or even most Confederate sharpshooters. Some liked the Enfield, but, as other sources indicate, those who were able to get their hands on a Whitworth considered it a favorite of theirs.
Hoosier