hey

i removed my exhaust yesterday and what i took off from where the downpipes bolt to the engine appeared to be allen head bolts, according to the yamaha dealer it actually has the stud and nut set up but the nuts just look like the head of a normal allen bolt so since mine have welded themselves to the stud i thought it was just a bolt...

so anyway can i replace them with some stainless bolts in the correct size or should i just get studs and nuts, reason is i could get the bolts today but have to order up the nuts.
cheers