I don't think those are the right bolts. Unless something has changed. I've done two of the 2015+ IRS assemblies, and in all cases the suspension bolts were flange head bolts and flanged locknuts. For the lower control arm where you're showing the 110MM bolt, my parts list shows using a M16-2.0 x 90MM flange head bolt, part number 15909. The inner connections for the lower control arm use a 110MM bolt, M16-2.0 x 110MM to be specific, part number 14925. Also flanged. I'd be a little careful using pictures as definitive proof. Often stock pictures are used to illustrate something, but might not be exact detail for your build. (My Gen 3 Coupe manual is full of Roadster pictures...) The captions or word descriptions are usually good, if details are provided. The box-by-box inventory list is a good source IMO of these kinds of details since it has exact descriptions, part numbers, etc. usually grouped with enough information to identify exactly what it's for.