i know im supposed to weld or put fiberglass first but is using just bondo ok?? what could happen in the future with my trunk with just using bondo??

 

it would crack. have shop weld the holes shut, shouldnt cost u more than 20 bucks

 

dont do bondo or you would have to do the job twice.

 

dont do it

 

Atleast fiberglass it first if you can't weld them up. The bondo is not for filling holes.

 

And now for an alternate opinion:

I do it all the time.
Ive bondo'd the holes left by the 'honda' and '2.0Si' emblems on the back of numerous third-gen preludes.
None of it has ever cracked and fallen out.
For larger holes from a spoiler, I would recommend putting super glue gel all over a quarter, or any other round peice of metal big enough to coverthe hole, then gluing it to the UNDERSIDE of the hole, this gives the top bondo layer something to sit on, sand it all smooth and paint it up nice.
Make sure that quarter is glued on there good tho or it will fall out and take your bondo with it....

 

if u can get to the inside of the panel sand it with 80 grit then use fiberglass mat and resin/hardener mix to bond it from the back then the holes should basically be filled from the back.then just use filler or fiberglass jelly on the top.I just went through this whole thing with my emblems and side molding holes.
or u could just plug it just in case u ever wanna put the spoiler back on.