Engine build/ aluminum in oil pan mystery

[StangerBanger]

i pulled the engine from my 94 GT this weekend and got it down to the shop this morning.. this is my first build, and i could not be more excited!!! i have already cut the seats on the heads as well as steel shot, pressure test and mag test, so most of what is left is block work.. anyway, when i took the pan off today on my lunch break, i found some shards of aluminum, which look to me like pieces of piston skirt... however, none of the pistons are broken, the timing cover is in tact, nothing is broken. its the damdest thing.. so i thought id share a few pictures with yall. i forgot to metion that this was a bone stock, unmolested 5.0 with 190,000 that ran like a champ before it was disassembled

 

[G_94_T]

That's alot of aluminum not to know where it came from