Panel/Bodywork bolt size?

[chunk166]

Hi Guys, I want to change the panel/bodywork bolts but i'm not sure on their size! i think that they might be M5,I want to change to Stainless like these
http://www.ebay.co.uk/itm/FLANGED-Stainl...2324wt_905


Is 16mm length going to be long enough or should i get longer & cut to size?


Cheers Ray