specs info for washer, screws, & nuts for Ottlite repair--TU

For Ottlite PL-0094 Touch Switch Hack, salespeople at hardware stores could not find find the 4 parts listed for this repair.

This is some of the feedback I received at the stores: 1.) what does "B6.4" refer to for the washer? 2.) The milwakee screws are only available in pan phillips M3-.50 --not flat Any info about how/where to buy would be helpful. Thank you.

**1. Wacker Neuson BPU2540 genuine OEM Washer B6.4 Flat. --what does b6.4 refer to?

*****2. [[Item:Milwaukee M3 X 15MM FLAT HD T15 MACHINE SCREW 05800015| ---Purchased: "Pan Phillips Machine M3-.50 "--but not flat***

********3 . [[Item:Dewalt NUT M3 0L36230112

**4. M3 nylon nut

--- Purchased "M3-.50 Nylon Insert Lock Nut". Is this the part?