The Schlage full size construction control key part number is 48-056-ICX. The ICX suffix will change depending on if the key is for a new job or existing job.
New jobs: Specify "ICX"
E...
Refer to Table 1 for a list of T lock tailpieces for conventional cylinders. Table 2 shows IC tailpieces. Table 1: T lock conventional tailpieces Table 2: T lock IC tailpieces