Hardware was as advertised but not what I needed. The L track has a 100deg countersink while these bolts are 90deg. I don’t understand they sell hardware that doesn’t match the L Track.

Didn't realize the 72" rails have 15 holes per side as only purchased one package of nuts and bolts which included flat washers only. Luckily my local Ace hardware had the exact same ss bolts and lock washers which I used when installing.

A little outrageous that these are not already included with the L-track. Each 8' section requires 25 screws, so plan to add $30 to the cost of each strip to attach it. As others have said, the countersink angle is atypical(100 degree), but can be found on mcmaster carr's website under Mil. Spec Stainless Steel Flathead Screws. This will allow you to get the length you need. Pricing ends up about a wash, so if you can work with 1.5" bolts, ordering them here is just fine.