I just got some extended A-Arms from fastlanemachine and I'm having some trouble with installation. I bought the entire extended kit which should have included everything for installation. During installation things went smoothly until I went to connect the Castor Blocks to the A-Arms. On my stock plastic A-arms there is a screw (28mm 1739) that goes thru the A-arm, thru the castor block then back into the A-arm. I tried using this same screw but the holes on the a-arms dont appear to be drilled for screws, there completely smooth. This combined with the fact that the kit came with a bunch of e clips makes me think I should be using hinge pins, but there were none includued in the kit, just e-clips with nothing for me to put them on....

Should there have been some hinge pins including in my extended arms set?

Yes there should be hinge pins I would them and tell them whats missing and the problem and have them send you the pins.