Need an opinion and some help

[BrushWolf]

I have a riser block that was glued up about 4years ago. I had started it but never finished it. Since then I've change a few things. I would like to go ahead and make something out of it but to do so I need to plug the threaded insert holes. My question is how should I plug them so I can redrill and tap them? Or should I just make a new one and put this one back in the wood pile? I just want to make sure it's safe so nothing pulls loose.    

[jess stuart]

I would fill the holes with jb weld or pc 7 let dry for a couple of days.  Sand flush and cover with fiberglass and drill new holes.  The glass will keep the bit from trying to follow the old hole.  I have used this method a time or two in the past and it worked fine.  
The limb locking kit we used to get from Binghams back in the 80 s used a 3/8 bolt we drilled a 5/16" hole and tapped it they held just fine and probably were much weaker than what we use today.

[Trux Turning]

I've done the same as Jess but I turned a hardwood dowel down to size, threaded it and glued it in- then covered it with glass before redrilling.