I think part of the confusion is because S&W used old photos of a previous generation 586 L-comp. In some pictures you can clearly see the rivet for the hammer mounted firing pin.
The L-Comp is a Distributor Exclusive PC Revolver from Camfour. The first 200 were manufactured in 2000. Small runs are done as Camfour needs more.
There is no doubt that a current production L-comp has a lock.
As to images on S&Ws website, most are not pictures. They are 3D computer generated renderings. As engineering changes occur over the years it is most unlikely that the image on the website gets changed.
Had a few from a batch that were not Camfour specials, Only differance was that they were 6-shot instead of 7. Don't recall the sku but I don't think they had a lock on them.