Hypnotoad said:
I would think junkyards would have them for a dime a dozen, unless you have your heart set on brand new ones.
I would go to the auto parts store first and ask them, may just have some in stock, then the yard is next... if all else fails you can go to mcmaster, or fastenal and get the size you need, found this on the OS:
GM# 11517155
M12 X 1.75 (metric 12mm in size---1.75 designates coarse thread)
10.9 Bolt grade / hardness (similar to an SAE grade 8)
Hex head with a loose but non-removable 3/32"(2.4mm) thick washer attached.
19mm socket fits hex head.
Bolt length measured from bottom of hex head to end is darn near 2" (50mm) (this includes washer thickness)
Color is light gray Zinc coated with light gray Thread-locker (Loctite) pre-applied.