Tilt a view bed extension

[wrapped]

We were looking for new mattress for our king tilt a view bed but only 76 inches long,just found 2 bolts 11 mm,on the sides at the foot of the bed rails,removed the 4 bolts foot rail pulls out 4 inches. Inner rail has 2 sets of nutserts, pulled rail out reinstalled bolts now regular king 80 inch mattress fits. MAKE SURE THIS DOESN'T INTERFERE WHEN SLIDES ARE IN!!!!!!!