wtf chain ring bolts

The chain ring guard came so I set about mounting the chain rings and
the guard. I ordered new chain ring bolts because I didn't want to
disassemble the old crank. The new inner bolts had hex deep down
inside and I figure that was fine until I could not find a allen
wrench that fit them. I tried both metric and standard and nothing
fits. The bolts on my old crank take a #5 allen.

Does anyone know what's going on?

I ordered another set of 16mm bolts and they look like they have a
larger hex that's not set deep inside it.

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C'est bon
Soloman