no need to install anything except the halyard! i did it, and its been 100% functional. see picture.
mount it all up, use the cheek block near the bottom of the mast below the cleat to raise, and cleat off. good to go. It runs close enough to the mast when raised so there isnt a problem to warrant drilling new holes to mount the fairlead
All that fairlead is going to do is chafe the halyard, so i chose not to install and i see no ill effects. Like i said, when raised, the line is close to the mast anways (IF you reeve the block correctly)
Also, the Murrays A Halyard has a pigtail....one for the forestay, and one for the block for the halyard. Attaches to the mast via the large shackle on the bottom.

pictured is my old starboard shroud, then the a. halyard assembly pigtail, then my new port side shroud on the shackle from top to bottom.
IMPORTANT!!!! re-tie the knot on the lower block of the a. halyard assembly. I didnt even check it (it came assembled from Murrays) and had my jib come down on a sail because of this kntt. I then had to purposely capsize the boat to re-attach!