they sell precut wood plugs

the fancier the woodworking store
the more wood choices theyll have
or you can order them online im sure
another option is a plug cutter

same idea but you cut your own
and if theres a space under your pickguard
thats not routed with a bit of meat
go for it(or dont,that could be disasterous
and itll match perfect
i use these things fairly often
and if you have a few to choose from
you can match the grain pretty well
and theyre tapered
so most of the glue stays below the surface
a dowel might give you a ring
unless you taper that a bit
but then you have the same idea goin
and if you line the grain up itll never split on you
other material doesnt expand and contract like wood
and then theres always these
