No, those won't work. 4-40 is the size of the bolt. It can come in many lengths, 3/8, 1/4, 1/2, 1 inch ,etc... The one in your link is metric 4mm x....
I ordered a box of them from these guys, along with a huge assortment of different size bolts, screws, washers, etc I spent last winter building myself and ultimate fastener collection from these guys. It has really payed for itself this year building all my planes!!!!
Just select the nylon screw section and look for the 4-40 stuff.
BTW, I tried the nylon bolts on my gear, but found the easiest landing still caused them to pop, letting the gear come off and scraping the crap out of the bottom of my plane. I went back to metal and haven't had an issue since. I also had to recover the bottom of my fuselage! I didn't even have any hard landings to cause it. Be very careful and don't overtighten the bolts, they have very little shear strength and you can weaken them significantly when installing them.
Good luck, hope this helps,