Indeedy...the 1917 Cylinder is shorter than other New Service Cylinders ( to allow the more generous Head Space for the use of Moon clips with the .45 ACP Cartridges )...and the little 'Lug-thing' ( sorry I do not know the proper name for it! ) on the side of the Frame which limits aft motion of the Cylinder when the Cylinder is open, is wider on the 1917s than it is on other New Services.
If the Revolver is .45 Colt, I would suggest you find a .45 Colt Cylinder to keep the replacement procedure more forthright.