ARP 2442901 Pro Series Flexplate Bolt Kit for Gen II/LS Series Small Block Chevrolet

I'm doing a 4l80 swap in my silverado 1500 which had a 4l60, are these bolts the correct length to go through my flex plate and it's spacer?

will these fit the LSA crankshaft and flexplate without a spacer?

Are these bolts a replacement or upgrade to gm performance flexplate bolt gm ls-series part number 19257940?

Will these fit a 2006 gmc sierra 1500 with the 5.3? I only have 3 bolts